roommate and payment for damages

[flowerchic]

This may be rather long, so please bare w/ me. Another person and I both signed a lease to rent out an apartment. We were not to have cats, but we BOTH had one anyways. We never got caught, but at the end of the lease, the carpet needed to be replaced due to cat damages. There were also other issues (like how clean the apartment was when we left) that we ended up having to pay for also (cleaning fees). To make a long story short, they contacted my roommate about all of this stuff (due to not having an address for me). She sent a letter saying that we were not going to pay, due to not being liable becaue they had sent a final bill to us 3 months for the carpet bill. Eventually, my roommate got a hold of me, and told me that they were going to get a collection agency after us. I went in and talked to them, and using my common-sense, realized that we were liable for the damages. To keep the collection agency of at least me, I agreed to pay them fifty dollars a month. I asked them if they were going to make her pay the half. They said that we were both legally responsible for paying the entire bill, and that they would not bill us separately (meaning that if it's not payed, they will attack both of us regardless). I contacted my roommate, and she said that she was still not going to pay. The apartment complex was very nice to me, and talked to me very maturely about this matter. I have been paying fifty dollars for a while now, and in the next two months, will have my half of the bill payed for. In order to keep the collection agencies off of me, do I have to pay the entire bill, then take her to small claims court to get the half that she owes, or can I just stop making payments after my half is payed for? Or can I take her to court now, and have the courts make her start paying her half. The apartment complex said to me that if I stop paying after my half is payed for, that the collection agencies will still come after the both of us and both of our credit reports could be damaged, even though I would have fulfilled my half of the responsibility.
I am really confused on what to do!!!! I don't want to have to keep paying fifty dollars for the next year, which could go to paying other loans off, just because she doesn't think that she's liable for any damages. I told the apart. comp. the truth about how we both had cats, and I wanted to do the right thing and take care of my responsibilities.
Please help!
Thank you.