October, beginning of November 2012 the situation will become very tense and dangerous.
Syria will be calming down a little bit end of this year (2012) or beginning of next year.
Within the first months of 2013 President Assad won't loose full control of the situation. I see President Assad doing a trip abroad (... timing not published publicly). On this trip the opposition forces will try to take him down by attacking his inner circle. There will be a lot of blood. It will not kill him but put him under real threat. The trip most probably serves to talk about the conflict, trying to find solution.
A higher instance (UN or a State) will lead a dialog and agreement will be reached.
The Opposition will still exist. They will gain more influence. They will play a role in Syrias future.