Vicki,
Take a look under your car in the area. See all of the screw penetrations there? Get a window caulk tube and go over every screw you can find. It might take a half hour to do. The other common area is the front bulkhead area where it meets the floor. This is probably easiest caulked from the inside (if you are a contortionist working for Cirque).
That is what would do if I were you.
Mike