Start another Borderlands playthrough
I'm about to finish my first playthrough of Borderlands. Apparently I'll be given the choice of restarting the game with the same character (playthrough 2), or continuing on playthrough 1. If I choose to continue, can I start playthrough 2 at any time? How would I do so?
Also, I haven't yet decided whether to get any DLC yet, but if I did I would like to be able to play it straight away. Do you have to be a certain level for any of the DLC? As far as the DLC is concerned, would I be better off in Playthrough 1 or 2?