I would seriously consider buying a portable field recorder that has a line-in
feature and supports 16bit aiff or wav recording. You could then record into the
device and simply transfer the data files over for editing on the Mac Mini.
Most of these units have removable SD cards so it should work well I think.

Check B&H Photo for an example of these kind of devices:
http://www.bhphotovideo.com/c/buy/Portable-Digital-Recorders/ci/14934/N/4291085915

(Disclaimer: I haven't tried this myself but it seems like a reasonable way to get audio into
a machine lacking audio input capability)


[ Edited by realstar 16.07.2012 - 23:11 ]