Sorry to say, but the BB's offered in September lately have been to be able to book a Free Dining package a year ahead for the next years FD - which are usually August-September/October dates. So when you go in September, you'll probably get a BB to book for 2011's Free Dining dates instead of any room discount BB for December or May 2011 dates.
And IF it's the same pattern this year, you would probably have to stay at a WDW resort starting toward the end of October/first of November to get a BB with the 2011 dates you're looking for (last year the FD BB ended on October 24 and a new room discount BB started with dates into the next year).
But this is just based on previous years after all, and it could be way different this year. Good luck and hope you get a good BB.
You don't even need a flyer in the room. You just call direct from your phone. Someone here will be able to provide the 4-digit extension number. All I remember are 8's and 4's. 8844, or something like that.
But just call the four digit extension from your room phone before you check out.