The pieces you are playing are some very challenging repertoire. As you get to become more advance, you have to realize the teacher is going to be playing less and less to insure that you begin to be more independent. That being said unless your teacher is a concert pianist, it is pretty unrealistic to expect the teacher to have every advance piece under their fingers. As a teacher you would want to give a good model of aspects you are discussing but that doesn't mean she cannot help you grow musically without showing you. You may potential have surpassed her technique-wise ,which is a result of great teaching, but probably have not surpassed her musically. If you are only 12 and playing literature that advanced, I would suspect she has a great deal of musical knowledge to pass on to you.
If you feel your progress in not improving rapidly enough, just take in consideration people improve in peaks and valleys, so there is not always a steady incline of improvement. If i were you, suggest she show you what her suggestions are. If you unsatisfied with the suggestions, it would not be the worst thing in the world to have a trial run with other teachers. Having a broad range of teachers can be very refreshing and aid your development. It it doesn't return you could always return. However i personally would give your current teacher the benefit of the doubt and try and increase the amount of communication of ideas. I am sure your teacher has a great deal more to offer you.