EW has confirmed that Comedy Central has renewed South Park for two more seasons, bringing the show through 2013:
The date for the second half of the 15th season of South Park has been announced! Comedy Central confirmed to EW that the animated series will be returning on Wednesday, October 5 at 10 p.m. The latter half of the 15th season will include seven new episodes.
The renewal will bring the show to 17 seasons.