My guess is on the fuel pump or the thing on the side of the tank opposite the pump (forget what it's called). Pull the rear seat bottom up, take off the protective cover, and you should be able to see the both the pump and the thing on the other side. Should be fairly easy to tell where the leak is from at that point.
Can you smell gas in the car?
Also, no you should not have any oil leaks. That's another problem you need to resolve. Chances are that it's either the oil filter housing gasket or the valve cover gasket. Both are easy to fix.