Okay, so you have established she is a manipulator. I think you need to ask yourself what sort of role she has in your life and whether you can cut ties or at least distance yourself. If she in fact is someone that you must deal with regularly in your life you need to think about and establish the boundaries of how that is to be. You also need to consider what it will 'look' like when she has pushed you too far. What I mean is decide now what the limits are to your relationship and what you will do when they are reached and broken.