I know. I had the pleasure of hearing her criticize my driving skills all the way back :D
You have three options there. All three involve being a total bitch:
1) Stop the car, make her get off and walk back home; 2) Stop the car, get off, get to the passenger side, open the door, push her to the steering wheel and let her drive (and begin cricizing her driving skills); 3) Continue driving, open the passgenger door, throw her out, drive away with a maddly mad grin on your face.
I trust my advice will be of great assistance in future ocassions.