The first thing I would do is take the front seats out. Pull the screws out of the thresholds and pull those out. Unscrew the seat belt bolts and pull the carpet...
You may or may not have to just pop the bottom of the back seat out to do this as well... Get everything dry.... Take the car outside and get a flashlight and have a friend or your wife or somebody take the garden hose and run it over the windshield and cowl area... Also auto shop A1A says because it's new doesn't mean it's works... Recheck the heater core...
