Spring 2013 seems to be the launch for Grand Theft Auto V, which would make sense as Max Payne 3 had a similar announcement.
Based on new advertising material, it does indeed seem as though GTA V can be expected next spring.
Images posted on the GTA-Five.pl forums, supposedly coming from a Sony store staffer, list the vague date. The photos say that it can be pre-ordered on the PlayStation and Xbox 360 – nothing about a PC version.
None of this is confirmed but for it to be a fake would be shocking.