For those interested, Jackie is referring to
this prior Q&A. It includes news of some significant changes relating to dining reservations this year. The good news is that when all is settled, we'll be able to make dining (and other) reservations online as soon as December of this year, if we desire.
The short answer to your specific question is that I think you are correct. It appears that you will need to wait until the launch of the new system, which is currently anticipated to be completed on October 24. My understanding is that starting July 31 you will only be able to make reservations through January 25. This will remain the same (no reservations beyond Jan. 25) until October 24, when guests will suddenly be able to make reservations from January 26, 2009 through April 21, 2009 (that would be an "interesting" day to be at Disney's central reservations!). Then, from that day forward, you will be able to make reservations 180 days in advance.
Please keep in mind that this is "new territory" for me (and everyone else), so it is hard to perfectly predict what will really happen. Please keep in mind...
1) Although the information I posted is "official" and is very likely to become fact, news like this is always subject to change
2) Disney typically is conservative in their estimates for timelines. OK, I know that didn't work so well with Test Track (!), but you know what I mean. ;-)
I think it is safest to assume for now that these dates are correct. I strongly encourage you to check back here, the WDW site, and your favorite unofficial Disney site for further updates as we get closer to your 180-day-window date (October 18).
Although probably not the answer you want, I hope it helps clarify the situation a bit.