The general rule is to increase your distance, time, or intensity by about 10% per week. You might want to taper back just a bit to where you're most comfortable, and then begin adding more mileage and time in smaller increments each week.

For fuel, everyone is different. A lot of people like oatmeal before a ride, and carb snacks during the ride. We like Nature Valley Oat 'n Honey bars for our rides, or dried apple pieces, oatmeal cookies or similar snack bars, and the like. Another thing I do is put a little O.J. (or apple juice) in the bottom of my water bottle, add a little honey (1-2 tsp.) and fill with water.

Be sure to not let yourself get hungry. Experiment and find what works best for you.

An excellent resource for learning about food as fuel for exercise is Chris Charmichael's Food for Fitness. He trained Lance Armstrong back from the brink of death to TdF victory, so I guess he knows a thing or two on the subject.