It says in your avatar that you are from "SF". Is that by any chance San Francisco?
If it is, you are in luck. California has some of the toughest puppy lemon laws in the country. No matter what your contract said, you had the option of treating your puppy rather than returning her. Since you kept her, your breeder is responsible for up to 1&1/2 times her purchase price for her vet bills.
Here's a good summary of the California law:
http://www.consumeraffairs.com/pets/lemon_ca.html