My Cat was attacked by my Room mates Dog, what should I do?

[jeni_0183]

My cat was attacked by my room mates dog as he was trying to protect a puppy who was also hurt (bruised nose). My cat ended up with a puncture wound under the chin, a cut nose, a swallon eye and was bleeding from the mouth, chin, and out of the nose. I took him to the Vet and upon furture examination, it was discovered that his jaw was broken and had to wired. The bill came up to $300.43, and he still has a follow-up to remove the wire, etc.
I am not willing to just give him away. I have had him since he was a baby, unweaned, I bottle fed him. He is my BABY!
I know that my cat and the dog need to be separated... He can stay with my boyfriend... Or at my mothers... I mostly want to know what I should do from a legal view...