Air conditioning salvagable?

[Loganator17]

I did some work on my van last weekend... Pulled out the leaky power steering pump and put in a rebuilt pump. I found it in a junk yard and put in all new o-rings. I decided to replace all the belts as the ones I had were looking pretty beat up. That's when I noticed the A/C compressor was locked up, and that belt has snapped! When I bought the van, the PO said the A/C wasn't working; this is the 1st time I've looked at it.

I'm not sure what to do. I want to just remove the stuck componenets of the compressor, clean /replace them, and get the air conditoner back in working condition. I have a feeling that this problem is not that simple, and I really don't want to mess with the R-12. The one mechanic I took it to told me he would have to pull the A/C out and install a completely new system (I'm guessing an R-134 conversion). From what I've read on this site and others, I either want to have the current system working, or pull it all out for weight saving purposes.

Finally, I don't want to put the new belt on the compressor and snap that one as well. Is this going to affect anything important, other than not keeping me cool?