I highly recommend
www.petfinder.com. It is a collection of humane societies, shelters, foster groups, etc., that advertise their animals in need of homes. Most of these agencies will charge an adoption fee, which covers the cost of neutering, vet visits, getting the animals up to date on shots, etc. I did a search on yorkies and many came up, but most were in NY/PA, few in NJ.
Please at least consider adopting an animal of unknown or mixed breed. The place you adopt from should be familiar with the dog's temperment, and every agency I've ever volunteered for has always been willing to take the dog back if it is not a good match with your family.