A leaked retail poster for the European version of GTA shows that the game will be released 'Spring 2013.'
The poster, below, shows that the game will be released for PS3 and Xbox 360, although there is no mention of any other platform for now.
It seems to make sense that the game will come out sometime after April, since this is the new financial year for 2k Games. There is also the fact that Bioshock Infinite will be released before next April, which didn't leave much room on the early part of the calendar for Rockstar's latest.
It's interesting to note that there doesn't seem to be a Wii U version announced for now.
Expect more details on the actual release date soon.