The pilot reported that he was on a return flight back to his home airport. He turned on the airplane's cabin lights, and they seemed a bit dim. He decided to stop and troubleshoot the lighting issue and refuel, so he would have full fuel tanks for the night flight. He parked the airplane in front of the fuel pump and refueled both wing tanks, before pushing the airplane back. He added that he planned on checking to see if the battery would charge before continuing the flight. The propeller turned slow and the engine did not start, so he elected to hand prop the airplane. The pilot stated that he set the throttle, mixture, and parking brake, and after several attempts the engine started. He added that the engine appeared to be at idle, and then the rpm's increased. The airplane moved forward and impacted the fuel station's credit card machine before he could enter and stop the airplane. An examination of the airplane noted substantial damage to the airframe's belly/bottom firewall area. Additionally, there was minor damage to the airplane's cowling, propeller, and nosewheel pant. There was also damage to the fuel pump's credit card machine and a set of steps. An inspection of the airplane by the responding Federal Aviation Administration Inspector found that the throttle's friction lock was working; however, a check of the airplane's parking brake found that even after application of the brake, the airplane would move and the brakes did not function as intended. Though the specific problem with the brakes were not identified.