Here's the "How to find a lost Yorkie" info thread:
http://www.yorkietalk.com/forums/gen...st-yorkie.html
I would contact your local animal shelters to see if anyone has turned him in and put flyers in local vets offices too, as dog owners are the ones most likely to pick up a stray dog.
Best of luck with your search. I hope Oliver comes safely home to you.
Please keep us updated.