I would suggest trying to switch your lesson times until you move. Or talk to the instructor about your frustration. Maybe she can put you in a lesson with more advanced riders, or you could ride a more challenging horse? Get someone to video tape you riding and watch yourself. Listen to everything the instructor says to other people and think about applying it to yourself if applicable. Read tons of books, watch videos of good riders you'd like to emulate, ask older riders for advice in your riding.
Good luck, I know how frustrating your situation can be.