Jan - I am not as confident as Melody that airfares will go down. I sincerely hope they do.
We too are booked for Nov '11 and made the reservation direct with Couples in April '10, and you cannot book air 18 months in advance. We were at Couples in June'10 and Dec'10 and both trips we paid just over $400/person for air. The same exact tickets for this Nov are $700/person. We typically try to book ~6 months in advance.
Yes, there is un-rest in the middle east and yes gas prices are sky high but airlines have also cut capacity. I fly alot for work and I'm seeing this in my every week travels too. For exammple, I always fly Delta. Last year, each day there were 3 Delta flights to MBJ from Atlanta, 1 flight from Memphis and 1 flight from Detroit. For Nov'11, all I am seeing are 2 flights from Atlanta and 1 from Detroit. If all airlines are cutting capacity this extreme, then that is yet a third factor impacting the higher prices.
The above said, don't get too discouraged yet and is haste cancel your time now. You still have alot of time to decide what to do and to be patient hoping that costs will go down. I'm not positive but I think you can cancel as close as 45 days out and get a full refund. Weigh all your options, alternate airports, crazy air schedule, low cost carriers. You may know this already...try
www.kayak.com, this site will compare alot of airlines and other discount sites in one search.