How to stop my car from leaking oil?

I have a 1995 1.9L Merc Tracer 4 cyl 88hp automatic front wheel drive. I took it to a mechanic and he told me that the oil sending unit is the place it is leaking. I am wondering where the leak whould come from and if it is easy to fix, whether if it is the sending unit or something else. I have to put in a quart of oil every 2 weeks or so. The puddle of oil is hardly that big (drops of oil) but my car could deceive me. I think I lose most of my oil during my drive to where ever it is I go to. Thanks