Are you looking for a pet or for a breeding dog? I always recommend the Yorkshire Terrier Club of America (YTCA) when looking for good breeders. They set the standard for the Yorkie, and the registry they use is the American Kennel Club. Here's are the ones listed in Michigan. (AKC)
Yorkshire Terrier Club of America About The Club The site has lots of great information on Yorkies. This brochure found on the site has lots of good information.
http://www.ytca.org/Breed%20Brochure...20graphics.pdf