The pilot reported that he was in cruise at 2,500 feet above mean sea level and was flying with an airspeed of about 120 knots. He saw a goose pass from left to right just above the engine cowl. The airplane sustained substantial damage when the bird struck the right wing. He declared an emergency to an air traffic controller and diverted to an airport. He stated that the smell of fuel was present during the emergency landing and he landed without further incident.