While this is a tough call, because the yorkie faces are just adorable. Please realize if you purchase the puppy you are saving one little one, if you call the spca you are giving ALL those poor puppies a chance at a good home. If you are loosing sleep because of what you saw ... I think you may be feeling sad about all of the puppies in general. Once the pups are taken to shelters, given meds, cleaned up, you will feel you've helped many and sleeping will come easier.
Hug, and good luck.