i have the same problem, and its your piston rings and/or valves. you need to get into that engine and replace the piston rings, and have a valve job done somewhere. you also need to replace the valve seals. if you dont feel like doing it yourself (i dont recommend it, since you probably need the cylinder walls honed) find a machine shop to do it for you. of if you dont want to spend the hundreds of dollars to have it done, its always cheaper to just keep putting oil in it. nothing will come bad of it in the short run, but u need to get it fixed if you plan on keeping the car and/or engine. just dont drive it too hard or else the problem may worsen.

btw, my car is burning 2 quarts every 2-3 weeks, i feel your pain! i am fixing the problem in the mechanic program i'm in. it should be fun!