I do not think there is any method for replacing a single hinge like that. Your best bet is to cut the hinges and then install new ones about an inch away from the old locations. This would also insure that no other hinges are loose or damaged (if you found one, who's to say that its the only one like that?). Given how cheap and quick the repair is, it seems like common sense to me to simply replace all the hinges. Just my $.02

P.S.: I guess there is a method to doing it after all. If you go with Stripe's method, be careful not to bend the aileron too much while cutting the slots (since normally the aileron covers the area being worked on, so gotta bend out of the way).