Hi Natasha!
If a special offer comes available for the time of your visit, be sure to check the special offer
deadline date, as this is generally the cut-off date most important to capturing the deal. You can go to the
Disney Special Offers link to see what offers are currently available. Then I would continue to check this link periodically. Historically, Disney will offer specials a quarter in advance. So, if there are any special September offers, you may see them offered as early as late summer.
In addition, if you find a deal you'd like to take advantage of, be sure to copy the PIN CODE down and call the Disney Vacation Package agents (407-939-7675) before modifying your reservation. I've taken advantage of sweet deals after securing my vacation, and mostly, they were able to modify my existing package to include the discount. There are, however, sometimes where they'll have to re-package your entire trip to get the discount. If you're staying at any of the more popular resorts (i.e. the Contemporary), there may not be rooms available for the re-package, so keep this in mind. But the Vacation agents will guide you along if and when the time comes.
Good luck! May your first trip to the U.S.A. be filled with memories to cherish FOREVER...