I'm curious as to what has made this character unplayable at level 3?
There are only 2 ways to rebuild a character in PFS after using it at level 2 at this time.
The first is if the choice is not PFS legal. If you apply something that is not campaign legal to a character you need to replace it with something that is PFS legal.
The second option is to be a tier 1 GM at Gen Con 2013. The tier 1 GMs get a special boon allowing a rebuild, but I don't recall seeing anything listing exactly what the limits of the rebuild will be.