I've just come out of year 13 (going to uni next month) and i had sort of a situation like this. One of my French teachers had a weird sort of grudge against me and marked my work a lot harsher than my peers', and also snapped at me a lot and generally made my life uncomfortable in her class. At the end of term she gave me back two of my essays with really harsh marks (10/25 and 13/25 - usually I would get in the 20s) and basically just ripped them to shreds in front of all of my friends, said I would be lucky to get a C at A-level, said that the head of French felt the same way, and I had to pull myself together because I would be lucky to even scrape a grade. Although I didn't show it at the time, it really really upset me. I have always been a straight-A student, and I thought stuff was a bit wrong. I went to the head of the French department, with my essays, and asked him why i had been given a 2/5 for grammar when i had only made 2 tiny mistakes. He said he had never seen the essays before, so i told him what my teacher had said.
He said he would sort it out, and he did. I went on to get an A (take that, lady). My advice is, ignore this teacher and do what you want to do. Speak to her superiors - they can make HER life miserable (as a change to her making your life crap). At the end of the day, you will only see her in school time, and only for a couple of minutes in the day. Don't get bullied in to doing something that will change your life. Your priorities are right. Hers are wrong. Stick to your principles and stand up for yourself.