your gonna needa buy a new reciver/dryer and new fittings. its actually pretty easy, evacuate the r12 in the proper manner, convert the r12 fittings to the r134a fittings, and remove the current reciever/dryer and replace it with a new one(make sure to leave it sealed and closed up untill the very last second) then recharge your system with new r134a and PAG oil. you can buy retrofit kits from kragen and do some research to find a dryer