Ahh that's simple, but you want to fix it sooner rather than later.
Get in the drivers foot well, hand on the tunnel behind the HVAC controls. There's a big pipe that goes into the floor. Pull it out and drain it into the bowl you brought along. Oh, didn't I mention the bowl? Well you'd better go and get it now then, cos you have filthy mouldy leaf sodden water soaking into your carpet
Clean out the end of the pipe and plug it back into the floor.
At some point you want to get to the top bit where the fan is as well, but that's a bit more involved.
C