1.25"/90 PSI tires like this:
http://www.performancebike.com/shop/...tegory_ID=5430 would speed things up a little. The tires you already put on likely are a huge improvement over the original tires, though, so stick with them if you like 'em.
Save your money for the new bike, and just adjust, fine-tune, clean & lube, etc. what you have.