I'm thinking of surrendering my old roommates cat
Why are you surrendering a cat?
I told her that I don't want to be a cat owner.
I feel sorry for the cat. If you made it clear you didn't want to be a cat owner, the old owner shouldn't expect you to care for it indefinitely. You should give her a deadline.
I guess I'll give her till Friday.
That's good. In the meantime, can you try and find a loving home you can send the cat to?