I do agree a bit that your desire for her to leave does sound like it has hit the unhealthy point.
Sprinkling powder in her office is unprofessional. If someone were to find out, you could face disciplinary action and you would probably would. Karma would strike you. Also, throwing the voodoo doll out the window? That sounds quite violent and over exaggerated. I have had an annoying manager once and he claimed I worshiped Satan when he saw my pentacle necklace. In my mind, I raged, but I kept it to a minimum and forced myself to focus on the tasks at hand until I got off my shift. Maybe try some deep breathing when she angers you. If you feel you shouldn't talk it out, then simply be the bigger person and be mature despite your dislike for her. If you want to go the metaphysical route, do meditation on a daily basis. Go out for lunch in you need a break. She probably will not leave, so you will either need to come to terms with this or consider leaving yourself for the sake of your career happiness.