I had the same problem as you when Mr. Biggs was a puppy. I had to spend an arm and a leg for all of his clothes, but it was definately worth it, because he looked so cute!
I'm selling a lot of his XS clothes on this thread:
http://www.yorkietalk.com/forums/showthread.php?t=68501
Also, if you wanna keep him warm for these cold nights we've all been having, I make fleece furbaby blankets. I'm working on getting a site set up for it, but for now I can take requests. Let me know if you wanna see examples!
Hope you find clothes for your little boy!
-Christina and Mr. Biggs