Signatory numbers have been steadily increasing for the petition. It was at 100,000 signatures around the end of November last year, then at 150,000 at the end of February this year. At the time of writing however it’s now cracked over 244,000 signatures! It actually only hit 200,000 just a few days ago, but the press coverage of this fact seems to have sent signatory numbers skyrocketing.
In terms of GTA V actually coming to the PC, there has been a few positive indications lately. The main one being this job posting at Rockstar. There has also been other rumors and LinkedIn profiles pointing to work being done for a PC version of GTA V.
Grand Theft Auto V is otherwise scheduled to be released on the Xbox 360 and Playstation 3 only on September 17 this year. Thank you also to the anonymous source of the (fan-made) wall-paper you can see above.