Assuming your gear inch calculations are correct, you don't need to buy anything, you need to spin your legs.

92 gear inches at a 90 rpm cadence is over 24 mph. You should be able to spin to 100 without any problem and that's good for 27 mph. If you can easily ride 27 mph and want to go faster, then call Team High Road or Team Slipstream. They'll give you a bike and pay you to boot.