defo no the a/c thats loosing oil anyway.. as above and the most likely problem would be the oil feed for the turbo.. also, have you topped up your oil since noticing the leak..? if its coming out the fast the sump will be dry in no time..
I've not driven the car since noticing the leak, and have topped the oil up, it's coming out really fast, i would guess a litre would come out every 3 mins, it's a constant trickle when the engine is running.
I'll get my ass in gear and have a good check.