You mean you have absolutely no access to another PC? If all your doing is opening and re saving the files so they can be transferred, the PC could be just about any quality. You can get one used for $50. You must still have your old PC keyboard, mouse and monitor.. Or I would go to a friends house. Do a bare bones install, do your transfers and delete Sonar.
What broke on the old PC? second hand parts?? My local computer store has boxes full of junk the sell cheap. You might be able to fix your PC for $10-$50.
Or as said set up a VM in the MAc, not a good system for serious work bu certainly you don't need much just for opening and transfers.