Ferrets are Carnivores. They will eat
eggs
bunnies
chickens
birds
you can keep them in a cage, transport them in a cat carrier, and walk them on harness and leashes. Do not walk them with just a collar because they can choke...

Frappachino
Mochachino
Twix
MnM
Thumper
Tinkerbelle
Thumballina
Tango

If it is a
Golden
panda
or any large breed, it will live about three years healthy
if it is a dwarf, it will live about five years.
When you hold it, check that it is not just lying there, that it is lively, has bright eyes,...

I feel sory for your cat!!! I don't know if there is anything you can do to help her though. *Sniff*