Where should I start if I have nowhere to go?

Okay, so here's the deal. My parent's are super strict and do not want me to pursue a career in the arts feild, that's why they didn't let me into Cantebury. Anyways, I want to be a filmmaker, a screenwriter to be exact. They refuse to give me the money to buy a good camera, all I have is my iPod Nano. We only have one family computer and my parent's are very strict on which programs to download. What should I do to pursue my dream? (In public or secret.)