I just rescued another dog a few days ago, she is an aussie mix, 2 years old.

Her previous owner couldn't keep her where she lived and had to give her up, and couldn't find a home for her, and didn't want to take her to the pound, so I took her in, I had them meet me at my boyfriend's house since it was a closer drive for the people to bring her.

And I like this dog a lot, I've only had her for 4 days now, but the only thing is she is extremely aggressive towards other animals.

I was told she was good with other non-aggressive dogs, and was total sweetheart.

Well first day we got her she attacked my boyfriend's dog, I know I wasn't to supposed to jump in but I did, Sadie kept chasing Charlie around the house, at first it seemed like they were just playing around, and things seemed fine until Sadie jumped on Charlie and started attacking him, they were both fighting pretty bad, I immediately grabbed Sadie's collar and pulled her off, but then my boyfriends dog didn't have a collar on so no one could grab him and he came back around and jumped back at her causing her collar to leave my hands, then she went after him again and was on top of him, my boyfriend's mom was screaming "Stop it!" and that's when I jumped in and I wrestled her off of him, but then Charlie came back around again and jumped at her, and she leaped up and jumped back at him and accidentally bit and punctured my right arm about 8 times, I got up and grabbed her trying to pull her off because she was just going at him, and there were no objects that we could distract them with, this happened in my boyfriend's house, in his small living room, Sadie had a strong grip on Charlie's neck, finally I managed to get her off of him, and I flew back with her into the fireplace, I broke her fall but hurt my back and leg, then Finally my boyfriend's mom grabbed her dog and took him in the room, and I had to drag Sadie outside, my arm was bleeding and swelling, but I had to take Sadie away from the house, I walked bare footed to a nearby park with her and sat with her until everything calmed down, Charlie ended up being okay, there was no blood, just a lot of slobber, I was scared that he was badly hurt, I had no idea she was going to act like that, my arm was hurting pretty bad, it went numb for awhile and kept swelling until my boyfriend brought me some ice, and then it started going down.

It was a huge commotion that night, and I don't ever want that to happen again, but unfortunately it almost did, I had spent the night at my boyfriend's house with Sadie in the room with me and away from the other animals.

My boyfriend's mother drove me home in the morning, and at first sight when Sadie saw my husky Shaddie, she wanted to attack her, luckily I had Sadie on a leash this time, I had to yell for my dad to grab my husky and take her in the back, because my husky was curious and wanted to meet Sadie, she kept coming foward and closer to her, I kept saying "Get back!" and she kept coming, while Sadie was going crazy on the leash trying to go after her, I immediately took Sadie into the house, and now have to keep her confined to my room all day because she absolutley cannot be around my other pets, she has tried attacking my husky and my rescued chihuahua, and my cat.

The person said she was good with cats, my dogs are non-aggressive, and that's what she said Sadie got along with.

I don't want to return her, as even though she is this way I really like her as she is good with people, she loves everyone she meets, but its just other animals that she has a huge problem with. None of my other dogs are this way.

I'm wondering if behavioral training would help her at all?
I want to be able to let her run around our yard, and get along with my other dogs, when I told the person that Sadie would have a playmate she said "Oh Sadie will love it, she needs a good playing buddy"
but obviously not Sadie can't stand other dogs.

What can I do to help this dog? I don't want to give her up already I want to try and make it work.

And watching the dog whisperer doesn't help, I learn a lot but what he does doesn't seem to work for me, I probably actually NEED him there to help out with her, other than that.. even though I have his books... it doesn't help me.
Oh and Sadie is up to date on all of her shots and is spayed/fixed.

I am feel really guilty about getting a new dog. I mean REALLY guilty.

My boyfriend and I have a dog together. it's really his dog, but we are together everyday, and the dog goes everywhere, and so it's basically our dog. He's a chihuahua mix, and the sweetest guy. We rescued him from a woman's house who didnt care about him, and had 10 kids running around and scaring him constantly. I've worked on him a lot and he is more socialized now, but still had typical chihuahua traits.

The other part of the back story. I have worked at a vet since I was 15 now. My first summer there, a woman brought in Chinese Cresteds and I fell in love. I have wanted one ever since.

Well I just got one two days ago. He just turned a year old, he was supposed to be a show dog but it didnt work. he is a "hairy" hairless. He is super sweet, but he doesn't play. He only plays with my cat, or my boyfriend's dog. I know I can get him to play, but I am not sure how? if I try to play with him, he gets scared. And he doesnt understand what chew bones, balls, rope toys, sqeaky toys.. nothing are. he just gives me a funny face. so in the morning or when I get home from work, he is all hyper and happy, and I dont know what to do! All I can do it pet him. It's wierd. He also doesn't make any noise at all.

So anyways, I brought him home two days ago. The second my boyfriend got here with his dog, I wanted to cry. I feel like I am replacing my boyfriend's dog. I feel horrible. I have been crying all these days. I have a week where I can take him back and have my money back. But the thought of taking him back makes me want to cry too. I realize it's only been a few days, but the guilt isnt getting any better. I just feel so torn. My boyfriend's dog doesnt seem that mad so far, but I love how needy he is of me.
I am starting to think maybe I got a mistake getting my own dog at all. I am also starting to think, as much as I love Chinese Cresteds, maybe I should have just found a Chihuahua, because I love all the expressions, the vocals, the needy part of the behavior. =/

I just don't know what to do. I dont want to keep a dog that I will feel I always treat second best when my other dog is around.
This happened before when my parents divorced, we had a dog at my mom's, and the dog from my childhood lived with my dad. Whenever that dog came to stay with us for a weekend if my dad had to go somewhere, I almost ignored my other dog.

I just don't know what to do!
I forgot to add, the Crested is the sweetest dog. He is playful with other dogs and himself some. And he is super sweet. He's a great dog, I do like him.
I paritally feel like I am so guilty I am putting up a wall between me and him.

I have a chi, who is 9 months old, he is good with me and somtimes my son, but when he is done playing he will growl or snap at you. also when we have someone over, he runs screaming to another room like someone is beating him, I have never had a dog act like this, and thinking about getting rid of him, but I don't think I could find someone who will take him. I called chihuahua rescue group, but they wanted 100 dollars to take him. I thought that was stupid. they said it was to have him neutered. I tried to house break him, thats impossible to. any advice would help.
He is 9 months old, I have tried to crate train him, but he just uses the crate as a bathroom, I have had a few dogs over the years, but this one is the only one I have never been able to house break, I had a cocker for 17 years, which is very old, but had to put him down when he got cancer, he was very hard to house break, but he was house broken after awaile it just took alot of time. I do spend tons of time with him, I also have a mini pin, who is very sweet and loves everyone, I was hoping my chi, would follow suit and learn from him. but my son is 6 and my concern would be a bite to the face or somewhere eles, if the dog got angry enough. To the person who suggested treats when someone new comes over, I did that with my sister, and it did work great. it took a few days but he then allowed her to play with him. so thats a great idea.