Could he defeat Christie in 2013?
Absolutely. Jersey is way beyond done with Mr. Presidential-wannabe. Christie stopped being Governor less than halfway through his term. If the Democrats don't nominate a more Republican candidate than Christie (a la Corzine Von Wall St) it'll be an embarrassingly easy incumbent topple. Though I wouldn't for a SECOND put it past Christie to pull a Romney and not run again in order to preserve his legacy for his definite Presidential run.
Plus, North Jersey is even further up Booker's ass than he is up their collective ass.