WARNING POSSIBLE SPOILERS AHEAD
IF YOU DON'T WANT ANY POSSIBLE SPOILERS IN THE FIRST FEW EPISODES OF SEASON 3 DON'T READ
okay so i was reading an article in which kirkman states that they are currently working on episode 8
so if they are just finishing up episode 8 that means the events of the trailer must be in the first 4 or so episodes because of how long it takes with editing etc so that means we may get a governor appearnce within those four episodes. more than likely within the first two episodes. here is the link to the interview
http://collider.com/walking-dead-season-3-robert-kirkman-interview/184180/