The kitty is lucky to have a heat lamp and kitty bed in this cold weather!

Karen has some very good points, but I also wanted to add...

If the cat has bitten someone keep it quaranteened (sp?) for 10 days to make sure it doesn't have rabies, and make sure the person bitten goes to the doctor, cat bites can get a nasty infection very quickly.

That big belly could be worms, or babies. Take Karen's suggestion and schedule a trip to the vet at the end of the quaranteen.

In the meantime, take a non frozen stool sample to the vet to test for worms.

Good luck.