Anne,
You can put in your ongoing search to be first in line, but you may still be too early for some of the resorts.
If the resorts are floating week resorts, an owner would not even be able to reserve a summer 2012 week until 12 months earlier -- meaning summer of 2011. Only fixed week owners are able to deposit 2 years out. Plus, many Mexican resorts will not let you deposit that use year until you have paid the maintenance fee on it. That would mean the depositer would have to already prepaid this years maintenance fees, next years maintenance fees (2011), plus the year after (2012). Prepaying maintenance fees can get messy because the dollar amount changes every year.
If you have a particular Cozumel resort that you prefer, you may want to look at one of the resale sites and find out if their weeks are fixed or floating. Usually fixed weeks are for the highest demand times, which for Cozumel should be December 15 through the end of April. So, I doubt you will have much trouble getting a summer week. I've even gotten Easter week at Coral Princess fairly easily a couple of years ago.
--- Rene McDaniel