It is very likely that your burners are clogged. You need to remove them and clean all the small holes on the side of the burner that is close to the pilot light. This is best accomplished with a welders tip cleaning kit, which is very inexpensive and can be picked up at any hardware store. In addition to cleaning the holes, make sure all of the slots around the top of the burner are clean. Also, turn the burner upside down and shake it, poping it against your hand to free up and remove any rust or deposits that may be inside the burner. If burner appears to be damaged or broken, replace it.