My puppy had to recently be put down because of a bad case of parvo. I was told to wait for almost a year to get another puppy and was wondering if it was possible for cats or ferrets to get parvo, or would they not be affected my the parvo that my puppy had?

Although cats can get a type of parvo virus, it is what we call species specific. This means that a dog who has parvo can't give it it a cat and vice versa. It's a similar virus, but it only infects its own species. (Likewise, it is not transmissible to humans.) So you are safe to get a cat or ferret.