SH,
Do you actually have the tools to do HVAC work?
Tools like:
- Refrigerant Extracting machine
- HVAC grade Vacuum pump
- Micron gauge
- Nitrogen tank
- Brazing equipment (& experience)
- Manifold gauge set
- etc.
You're going to need to assemble (at least) this set of tools to solve your problem.
Also, if you want to keep this beast in the R22 world, you're gonna need a HVAC ticket to get any more R22.
Do you really intend to do all that?
-AC