I would take a picture of her and make a flyer (or one without a picture if you don't have one). Put all the info you can on there and give them to your neighbors. Then put them up at pet stores and shelters.
Have you called the shelters and animal control to see if they picked her up?
Also, I'd just kinda walk/drive around the neighborhood and look for her. Leave a bowl of wet cat food out and see if she comes to get it (watch for her).
Is she indoor only? Where do you live (country/city)?