Though at only level 20 I have done a lot of the main quests and side missions, will the patch mean I have to start over ?

Why would they release a patch that would require you to start over...?

You won't be able to redo some of the broken quests if you've already completed them, though.

not sure about that. i want to know if it'll do something about my growing population of louis letrush.

your generally better off starting again after a patch has been released