ive been told not to feed them untill they have been in there tank for an hour at least.
i dont see what harm it will do by puttin the oxygen on n light
I'd wait until tomorrow to feed her. I'd also leave the tank light off so she can settle in better. By 'putting the oxygen on', do you mean an air stone or filter? In either case, it wouldn't hurt to turn it on now.
I would still be tempted to quarrintine her for a week or two in the 5 gallon. Also, remember that not all females will be sucessful in a community setting so hopefully you have a back up plan too! Congrats and good luck with your new girl.