The certificated commerical pilot reported that during the takeoff roll, just before the airplane reached flying speed, a sudden gust of wind pushed the airplane to the left. The pilot stated that he tried to abort the takeoff, but was unable to stop the airplane before reaching the end of the airstrip. The airplane rolled to the end of the airstrip, down an embankment, and collided with brush. The airplane sustained substantial damage to the wings and fuselage.