I would try to bend the tube back to where it should be, maybe slide a 3 or 4 inch 10 ft stick of PVC pipe over the tube and slowly bend it. The old gas cap on the tube may prevent the top of the tube from distorting. Also, the tank will rust if it is not painted, here is the paint I've used on mine;
http://www.yearone.com/serverfiles/p...hid=523AN65475