I think its typically 80 - 100rpm that the books recommend. Although I don't actually measure this when I'm riding, and it would vary slightly depending on terrain.
If you want to get good at cycling - go and join a local bike club. Your bike handling will improve, you can follow their examples, and more incentive to get out for the long runs on a weekend.
You need a big base of steady miles before you can begin working on your speed.