For this coming October, you will have the existing (2007) plan. Although I am not sure how much luck you will have getting ADRs at such a late date. Best of luck!
You get the Dining Plan in effect during your stay. If you arrive in 2007, you get the DDP in its current form. If you arrive in 2008, you get the 2008 DDP. If your stay includes December 2007 into January 2008, you still get the 2007 plan.