THis is what you need...
R22 is out and should not be used.. you will have to change your system to R134a.
Besides modifying your aircon... you need the following items
1) Vaccum pump..
2) set of guages and charge pipes.
3) Depending on your system.. ie .if all the pipes are welded/brazed/or soldered...you will require a porable oxy/accet. kit...
4). Refrigerant recovery system.
5). New gas, + all the new components to modify your aircon...
After you have purchased all these items.. you probably have spent more than you would have buying two or three portable aircons..
Call a qualified tech.
paul
July 2006