The Brick Blogger posted this image of a heretofore unreleased Lego Batgirl minifigure that somehow escaped from a Lego factory in the Czech Republic. It is presumed she will be released to the general public sometime in 2014, possibly in one of the following sets scheduled for release next year:
#76010 LEGO Super Heroes The Penguin Face Off (with Batman, the Penguin, and 2 Robot Penguin Henchmen)
#76011 LEGO Super Heroes Man-Bat Attack (with Batman, Robin, and Man-Bat)
#76012 LEGO Super Heroes The Riddler Chase (with Batman, the Riddler, and the Flash)
#76013 LEGO Super Heroes The Joker Steam Roller (with Batman, the Joker, and 3 other minifigs)
Since the only set without all the minifigures specifically named is The Joker Steam Roller, we can assume Batgirl will come with that set. It is also the largest, and therefore most expensive set of the new releases, so yeah, that figures!