To the OP, don't get frustrated, the perfect little rescue is waiting for you somewhere.
I've been looking also, and will admit that a younger pup would be ideal, but I'm open to adopting an older yorkie too... I do have 1 criteria, It has to be a boy!!!!
Don't ask why, I just have my heart settled on finding a boy. Just when I think I've found the perfect one, I get to the shelter and they're already gone. Oh well... that'll teach me for choosing to take my final rather than checking out the yorkie boy at my local shelter.
At least I got an A in my class
In all seriousness, there are lots of places to check, petfinder is great but you can also check your local shelters they sometimes have cute yorkies and yorkie mixes, and if was meant to be they'll be sitting there when you arrive!! Just be optomistic and keep looking. Then you and I can celebrate finding our perfect little rescues!!!