I deal with this as well. Fortunatly, right now my school doesn't have enough money to purchase animals for dissection, so I should be able to get out of this year's bio class without having to deal with it.
However, when I was in jr. High school, before I finally decided to make the transition, my 7th grade science teacher and my 8th grade animal science teacher (the same woman) had us do dissections most weeks. Among the worst: pigeons, a full grown cat, a pregnant shark, starfish, and of course the traditional frog, squid, worm, ect. At one point I counted how many animals I dissected or did "behavior experiments" on during those two years, and the number made me sick.
The only choice we had was to try to get transfered to the one science teacher that didn't require dissection. Unfortunatly, I chose not to be transfered because the woman was an incredible teacher, a living legend that everyone remembers long after they've left the school.
I'm all for you trying to make your school give students a choice. But don't feel like you have a deadline.... if you can't get results this year, remember next year's students. These things can take some time.