Anyone know the timeline of when this was filmed?

It was released in 2010, but does anyone know the filming timely? It seems like it was filmed over a period of time (different locations and different hair cuts) I'm assuming filming began as early as 2007 (maybe earlier?) and filmed as late as 2010, or was it wrapped up in 2008 or 2009? I know they showed the Colbert Report, which was during the summer of 2008, so it was at least until then. Does anyone know?