They do make left handed pistol grip Tx's. Most of the time, you can do either with the same Tx. I have the Spektrum DX3R and I can do either. But you pay to play with that Tx. But there are others out there that can do the same thing. If you only have control of your left hand, you could set it up so that you can control the throttle with your trigger finger and the steering with your thumb. I have driven like that in a race when I had something in my eye.
But they are out there, I suggest spektrum. That is what I use and love it. If not that, look at the Airtronics M11. You should be able to get it pretty cheap.