Has your cat been chipped?
If he/she has, its worth mentioning it on your flyer, we lost our cat last year (a rather large mean looking British Blue tom) and after a neighbor mentioned he would love a cat like ours, we changed the flyer to mention he was chipped and within hours of posting locally, he was back on our doorstep, looking very fat and smelling of perfume!
Its also worth posting the flyers further than you think, they can stray quite a distance.
The other time we lost him, I ended up doing a 2am walkabout and calling for him, he was asleep in one of our neighbors bedrooms and came crying to the window when he heard me!
Good luck, I know how it feels not knowing where they are, its not nice.