Call back & speak with another CM! The AAA rates came out today. (I got my discount applied this morning.) Just tell them that you want the AAA discount applied to your room-only reservation. (They may ask for your AAA membership number, so have it handy.) I'm not sure you can do this online, but you can do it by calling CRO -- you don't have to go through your AAA office unless you want a AAA package.
If you are interested in purchasing park passes separately (i.e., not part of a package), then you can purchase those through AAA for a discount. Look on your local AAA office's website to see which tickets they offer. Each AAA location seems to offer different tickets and the options are pretty limited. For example, they may only have 4 day or 7 day tickets. If they have what you want though, they are a good way to get your tickets -- maybe even a little cheaper than through UndercoverTourist or Ticketmania.
HTH!