Rep Power: 0

My car is overheating and I have a feeling it has something to do with a leak since I've seen on my driveway it leaks sometimes. I fill up my Reservior and the coolant will sit in there, but then I take it out for a spin and when I notice it starts overheating I stop it and park it. next thing you know the resorvoir is slowly getting low, any body have any idea what's going on?

 
Rep Power: 518

In addition to the reservoir, you must refill the radiator itself.
Note how much you add to it.

 
Rep Power: 0

"I stop it and park it. next thing you know the resorvoir is slowly getting low,"

That is what it is supposed to do. As the coolant cools it contracts and sucks more coolant from the reservoir back into the engine. If you are persistently using a lot of coolant, check for leaks or possibly HG failure. If it is leaking from the timing end of the engine, change the water pump and timing belt pronto! Coolant leaking onto the timing belt will make it snap.

 
Rep Power: 208

Can you smell coolant (sweet smell)? Is there STEAM coming from the tailpipe? Is there white residue on near/on any cooling system parts?