sounds like bad rings to me
try a cheap fix first before you go tearing down the motor....
1) buy a bottle of engine flush... gunk engine cleaner is typically available from parts stores, but I recommed BG quick clean (check ebay).... run this crap for about 10-15 mins AT IDLE... this will hopefully clean off any crap off the ring packs and free them up so that they will do their job again and reduce oil consumption
2) change the oil immediately after the motor flush... I recommend getting some cheap oil and a cheap filter for a 2nd rinse (for like 5-10 mins) to get rid of the flush (that stuff is evil to oil).... then put in a quality high mileage oil (valvoline maxlife or mobil1 high mileage)
the high mileage oils are not gimmicks... they have seal conditioners, additional detergents, and have been engineered to have better shear resistance.... I suggest going to a 5W40 or 10W40 oil as it is more shear resistant and helps prevent burn off
if that works, then just keep on motoring for now... a motor rebuild or new motor costs money.... it's your prerogative of course