This are 2 images from a polish site. The images must be real, the artwork is very well realised and Rockstar took down the site who posted it. Also on GTA V Pest Control post an Admin said that any leaked content commented there would lead to user's ban.
So here are some stats:
Release Date: Spring (March-May) 2013
Released For: XBOX360, PS3, PC possibly released later as it is not listed