
If you'd seen the conditions the puppy was reared in why did you pay the breeder and encourage her to produce more the same?
I don't think there's a lot you can do - caveat emptor applies to the sale of puppies along with many other things. You had the opportunity to examine her before you took her, so in effect you've 'accepted the goods as seen'. Has your vet checked her out yet?
Other than that, you could try reporting her to the RSPCA and the local council.