I second the suggestion to call Animal Control every day. I find strays all the time - in one case I called A/C several times during the course of a week - and so did the dog's owner - it took A WEEK before someone put two and two together and realized the dog I had belonged to the lady missing a dog of the same description. This dog even had a bright green collar (no tags) and they STILL didn't put it together.
Call. Or go down there. Every day. Leave flyers there, too.

Hang in there. I know I would be frantic if one of my girls were missing.