S.A.F.E. Animal Rescue in St. Augustine says they have 5 Yorkies right now. Have you tried Petfinder.com?
Sounds to me like the shelter dog isn't really what you want. If you can wait and be patient, I'm sure the shelter will get Yorkies in. I went online looking for Lola for a whole year until the right dog came along. I know that's too long to wait, but it sure beats "settling" for a pup that you really didn't want. That's not fair to the dog.
I'd be skeptical of any breeders that only want a few hundred dollars for a Yorkie. Just remember, you get what you pay for.
Petfinder Adoptable Dog | Yorkshire Terrier Yorkie | St. Augustine, FL | Pebbles