I'd just get a junkyard AC motor and take it somewhere to get recharged afterwards. It's not worth getting a NEW part for it.
Do you have emissions inspections in your state? If not, lose the cat and have a muffler shop weld in a straight pipe. It'll sound nicer too.
If you do have emissions inspections, you'll just have to get a new cat. Just look for a generic OEM replacement if you want to save money on it.