water in the rear of 01 blazer

I got back from a road trip over the weekend where it rained for 2 days straight and the carpet in the rear of my blazer was soaked.  The carpet on the passerger side rear is much more wet than the other side.  I have noticed this before, but it has never been this bad.  It sounds like water is sloshing around now in the rear of my blazer.  I have pulled up the carpet and taken off a good amount of the moulding and I can see down in the little holes where it is all wet down there.  I am trying to figure out a few things.
 
1.  How do I get that water out of there; everytime I get in my car it smells like standing water.  I have crawled around under my car, but I don''t see any drains or anything under there.
 
2.  After having someone spray my car with a hose I have determined that the water is coming in from the plastic piece at the rear the rear window on the passenger side.  It appears to be coming in thru the bottom hole.  I''m not sure the best way to seal that up or how those plastic pieces come off.
 
I appreciate any bit of advice I can get.

Can you take some pictures of what you are talking about and post them?

I know it has been awhile since you posted this, but I was just wondering if you had any luck with the diagnosis?