mscat, I am glad to hear that you got your puppy and that all is well
I have a 3lb puppy of 5 months and I can't wait for her to grow. She was about 1.2lbs when I got her and although she is the healthiest, happiest puppy I have ever known, I am always afraid I might hurt her.
My other one, Cash, is 10lbs and June keeps up with him! She wrestles with him, chases him, plays tug-of-war with him, everything. Sidebar: I think Cash has fallen in love with June

!
3lbs is very small for me, June is really tiny. I mean, she is just a puppy and will still grow some, but if she should stay this size, I would be sick with worry the whole time. I am hoping she gets to be at least 6lbs.
For me, the problem with buying such a small baby would be the breeding practices behind the small yorkie. If it was purely an accident of nature, it is fine, but if she was intentionally bred to be small, I would be worried.
Small yorkies are beautiful, but then again, small for me is between 4 and 6lbs. I would never own a smaller yorkie, but that's just me.