Converting A/C to R132a?

[Dooley Dude]

I last had working a/c in my truck many years ago, when I put in a new compressor and receiver/dryer, pulled a vacuum and charged the proper amount of oil and R-12. Worked great for about 9 months, then the compressor (a cheapie reman unit) leaked out the charge.

I would like to fix it again, hopefully with better results, converting to R132a. Other than a new compressor and receiver/dryer, what do I need to do to make the current system work with R132a?

Edit: I guess I mean R134. Whatever refrigerant is commonly used these days.