Have you checked the Yorkshire Terrier Club of America's website. They are a good place to start - reputable breeders' club. (ytca.org) They have a breeder referral page to find a breeder in your state/area.
If you are screening breeders not on this site, just a few tips. Reputable breeders do not place pups before 12 wks of age. They need this time to mature, socialize, and reduce risk of low blood sugars. There is no such thing as a "teacup" - marketing ploy. Breeders should want to interview you and make sure you will provide a good home before placement.
I wish you good luck in your search for your new family member!
