Mercedes Benz repair: water soaked driver floor mat, ridicoulous, 2000 clk 320

Question
I have 2000 CLK 320 cabriole convertible and water soaks the driver side carpet when it rains. My online research seems to indicate that I have a clogged drain for the water collector that is at base of the windshield.  I was able to locate and clean the drain of the collector on the passenger side, but am unable to find the drain on the driver side.  The dealership said the problem was "upper windshield weatherstrip (leak) (SOP) and estimated $330 for parts and $535.05 for 4.5 hrs labor.to repair the problem.  The service manager claims there is only one drain (on passenger side), but what I've read indicates that there is a drain for each side - although no one can tell me exactly how to find it from below (so I can clear it from there). Being able to get an eyeball on it from above would require quite a bit of disassembly that I would like to avoid.
If they are right about the upper windshield weatherstrip being the problem, the estimate for repair seems very high to me, and I suspect that I could do it myself,with some instructions, for a lot less.
Your opinion would be greatly appreciated.

Answer
you could probably get away with doing it yourself of course, i think stealerships are a little ridicoulous on there pricing guides thats why i dont go to dealerships generally unkless for hard to find parts. I would suspect you could go to www.benzworld.org and fil out a profile and answer the watercollector problem to one of the people in there, its an obvious problem that im sure people on there have had.