As varjak paw stated the iMac would need to have some sort of USB interface, the difference between line level and mic level is not a quality issue, it is a nominal electrical db level (not db as in sound pressure level, but db as used as a measurement unit electrically) line and mic level are approimatley 60 db in difference electrically in a log scale.
That being said, I just checked using a transformer on a sm-58 into my 13" and although it would "see" it the levels would far below a usable signal.
Can't speak for the Sony software as I am not familiar with it, and I don't use Windows (at least not for a long time).
I suppose you might be able have someone write some code maybe, but buying the equipment that is required would be much less expensive and easier.
Many choices of interfaces/preamps on line in many price/quality points.
Best