oil leak..

If the engine has been leaking for some time (and it sounds like it has), the engine and drivetrain needs to be throughly cleaned first to get rid of the mass of oil splayed all over the undercarraige. Then, have a shop add small bottle of oil leak detection dye to the crankcase, and drive the car a few days to get the oil leaking again so the a shop can find the leak. From there, they can assess what need to be done to fix the leak(s).