I think that the disney dining option can only be added if you are getting a vacation package - not just tickets. I would check out the restaurant board for some great tips.
One option depending on how long you are going to be staying, and what types of places you will be eating - Disney Dining Experience (DDE) card. As a non-FL resident, non-AP passholder, this just became available to me. It is $ 75 per year and it gives you 20% off your dining and drinks at most sit down restaurants. If you are planning on doing mostly counter service restaurants, then it doesn't make sense, however if you are eating mostly sit-downs, then it might. I checked out Deb's site for menu prices and for us (4 adults & 2 kids) it is a great deal.
Happy planning.
Pam