Auto Trans Leaking

[anarchyok]

Hey guys, a week after dropping some cash to get new front pads, and a left front bearing, the auto trans, which has never given a lick of trouble, has started to leak a small pool of oil. Is my amateur diagnosis of either a loose screw holding the pan on the bottom of the trans housing, or the seal on the money?

What kinda of cost should I expect for a new seal and auto service?? Is it an easy part to fit with a little know-how?