The EPA changed some rules over the years on what type of refrigerant is used in the vehicle A/C systems. If you have the old coolant, you can't get it charged anywhere. Take it to an automotive garage that does A/C work and they should be able to hook you up.
Basically, they check for leakage within your A/C system, repair any lines or O rings required to properly seal your system up, then draw out (capture) any remaining old refrigerant in your system and then charge your system with the specified amount of the "new" refrigerant.