Gears- Diesel -What car to buy

I would appreciate it if you could answer a few questions for me.
I have no idea what category to post this in so I chose this as I am considering buying a Clio


1. Diesel or Petrol? What is best? What are the main differences etc?
2. What are the new gears all about? Multimode/Easytronic/Multitronic etc?
3. Can you recommend a car for me to buy. I have a permanent disability in my left knee so I can't use a clutch. I have been driving an automatic Micra but I seem to have a talent for killing automatic gearboxes. I would like something cheap to run with low insurance and it must be reliable. I want something a bit more powerful than a Micra but I don't really want anything bigger. So something the same size as a Micra but with a bit more go in it would be ideal.

Thanks