Don't know if you've made your reservations yet, but I found a great deal at Banana Beach through www.summerinbelize.com.
A room for $375US for 7 nights, including tax. We added 5 nights, for a total of 12 nights for $645US.
Now, if only I could find cheap flights!
Husband and I are going in mid-Oct. Our first trip to AC and I am already addicted to this board. Can't wait - this trip is what is getting me through the summer (the worst time in my job).