Well I'm from a flat part of Ohio as well. But if you are close to the PA line there is some great climbing some grades 14% and a little better.

Anyway as far as getting faster without changing your bike try riding in bigger gears and trying to maintain the 14mph pace for a while (two rides a week). Then when you return to the smaller gears you are used to it will seem like you are flying with less effort. Because you have built more muscle mass. Quickest way to gain watts is to loose weight so you don't have to pedal as hard or gain muscle so you can pedal higher watts without noticing a difference.