your car should have cut out 100 yards after putting the fuel in. Once you have managed to drain the fuel out and put petrol in everything will be fine. Your car is computer managed and it should have simply stopped so not to cause damage. It's not like it is an older car that would have continued to suck the fuel in, blow loads of smoke and stutter to a halt.
You also didn't need to spend 200 beans on it either. I spent nearly 2 hours draining the fuel tank of a vw beetle that bad anti theft devices on it. The car is now running just fine.
Don't worry, it's really not that bad, it will be fine in a few miles and a bit of smoke!