Nope. It was just the mid-season finale. The rest of the season premiers October 5th 2011 (http://www.southparkstudios.com/fans/faq/). Usually when television show creators put out a final episode, they'll state that it is. After this season, though, Matt and Trey have the apportunity to renew their contract with Comedy Central. If they say no, then there's really no way of stopping them.
But like I said, if that was the mid-series finale, I believe they would have said so. We'll just have to wait to know for sure, though.