Since the compressor failed internally, you will need to do much more than simply replace the compressor. Upon compressor failure such as this, there is debris strewn throughout the system that, if not TOTALLY removed, will wreck the new compressor almost immediately.
You need to THOROUGHLY flush the system everywhere. Break apart all connections and use LOTS of flushing agent throughout everything, then flush again, then again, and after that flush it again. Then ENSURE that you have removed all flushing agent.
After flushing EVERYTHING, replace the filter drier and evacuate thoroughly before recharging with R12. These cars have marginal a/c capacity, so going to any refrigerant other than R12 would be a mistake.