I think you will be way ahead doing it yourself. Get a Tama or Zexel or some such in R-12 or R134a configuration (I like the yellow/black stickered compressors made by that company). In the R134a configuration, you get no ports on it, but you get them on the R12 unit. Get matching o-rings from discount, a new drier ($30) and some ester oil to lube the o-rings and to change oil in the compressor if necessary. Snug the fittings, don't overdo it, and then take it in for a pump down and fill if you do not have access to a vacuum pump.