Adopt-a-Pet.com :: Adopt One of these Great Dogs !
There's petfinder as well... some of the smaller cities, animal shelters, in E WA list there.
It seems once a yorkie makes it into a so called rescue, the prices jump astronomically. This one for instance: $700
Seattle, WA - Yorkie, Yorkshire Terrier. Meet Simba BB a Dog for Adoption. I was speechless until I saw he's being flown from CA....
Have you checked with your local shelters to see if they have some sort of list to get onto?