My first suggestion would be a thorough inspection of the mast for leaks. A mast with water in the end will definately keep you from righting the boat.

My second suggestion is to review the "power righting" technique shown in the Murray's catalog, in which the boat is swam so the mast faces 45 degrees into the wind and then righted. The more wind, the more effective this is.

A friend of mine swears by cleating the jib down so it forces air under the main. I haven't tried this.

HobieGary sells the Solo~Right tool which doubles as a paddle. There are various models of this tool which will allow everything from 14'x7' to 21'x10' boats to be righted single-handedly. I do no have one yet, but it's on my wishlist. It is definately not class-legal, especially with Hobie Cat being the most anal Class Association out there.