You should wait. Fares purchased now for autumn travel are expensive, as they are every year. Historically, fares drop in late August and early September. As flyinbob said, the travel market is soft, so the airlines probably will drop pricess just to fill the seats.

If you see something now that you can live with, you can buy now, then re-fare if the price drops later. Are you seeing any fares that fit within your budget? I sure don't see anything that would make me pull the trigger right now.