Thanks! I did get it from a local shop. I wrote to the woman who sold me the bike and we will see what she says.

According to my bike computer, I averaged about 12 miles an hour, but was much slower on the uphill (it is a very slight grade)- more like 9-10 mph. The fastest I ever got up to was 13 mph and that was on the downhill.

When I tried to shift up to a higher (more difficult) gear, I found it too tough to pedal at all for more than a few pedal strokes. I thought I did understand shifting but I guess I don't?! The bike is a compact... so when you say middle gear are you referring to a triple?