Getting out of contract that has not started yet.

I have been living in an aprtment comples for 2.5 years, and my current lease is up August 31st. My landlords require me to sign a lease renewal 90 days in advance, making it due May 29th, 2009. I signed and returned the renewal stating that I would like to renew my lease for another year. A few weeks later, an opportunity to move to Florida came up, and I am in need to relocating financially. My lanlords are telling me that I am basically screwed, and they will sue me if I break contract. Is there anything I can do since my new lease technically didn't start yet? Or am I stuck? Please Help!!