You can dial Disney directly and see if there is a AAA discount available for your dates. If there is, you just give them your membership number and you can book it right away. Then you'll need to show your card when you check in.
As far as a discount for next month, you never know, but there's a limited amount of rooms available with the discount, so I'd be kind of surprised if there were any left. But it never hurts to try!