There are a couple good web sites: www.felinediabetes.com and www.mycathasdiabetes.com.

Cats can go into remission; I've seen it happen, and there are loads of examples on felinediabetes.com. There's a diabetic in our rescue. It's interesting how different vets manage it. He's on Humulin, which is kind of surprising, but is doing well.

Good luck with Tilly!