Sigourney Weaver says Avatar 2, 3 and 4 to start filming this fall . . .
Director admits that he doesn’t have time for anything else besides Avatar 2 and 3 and perhaps 4 . . .
Actress confirms that she will appear in both sequels . . . one day.
Cameron to produce remake of ‘Sixties classic . . .
Director reveals a bit more about Avatar 2 and 3 set for release in 2014 and 2015 in TV interview.