I am attempting to reinstall ubuntu 13.04 without losing my installed software and /home docs. I have read countless threads on this same topic, but nothing seems to apply to my situation. When I originally installed, I had created a separate partition for /home, but I am now unsure of which partition that was. Based on the picture below, where should I be installing the new copy?

Also, will I run into problems since I am now running 13.10 and want to put 13.04 back on it? Should I grab 12.04 or 13.10 for this reinstall?

Picture: http://i.stack.imgur.com/FL2SY.png

(Note: I am performing this reinstall due to a complete muck up of my unity/compiz settings and configuration, resulting in no desktop. I've done my best to resolve this problem first before resorting to this.)