Paint & Body Work - my car sprung a leak...

OK so when it rains im taking on water. Unfortunately, I didnt catch it until it was too late. By the time I got around to pulling up the carpet it had already developed a bit of a musty odor. Fearing a losing battle with mold i cut the section out and went down to the bare floorpan. So now my car is a lot noisier on the road and i have no floormat on the d side. Anyone know of a good way to replace just a specific section of carpet?

Regardless, I still havent found and stopped this leak, and it continues to rain...

It looks to me like the water is coming down the firewall, right by the dead pedal to the left of the clutch pedal and then streaming over the rest of the floorpan. Anyone got any ideas as to where the leak could be? are there problem areas I should be looking for? For that matter does anyone have a good method of tracing such things?

I was thinking maby the windshield or HVAC or something...

I had a leak in my car and I pulled all the carpet out and followed the trail of surface rust it created in order to find it.

Candidates that I can think of:
* Windshield
* Hole in firewall for brake booster
* Rubber grommet that goes between the door and the car (ends up about 6" to the rear of the vehicle compared to the dead pedal)

I had this and it was the grommet for the hood release cable