Thanks Sparqee, that makes me hopeful that this won't be as difficult a setup as I've been anticipating.
I found this Audio Interface, at least I think that's what it is, on Amazon... and I found it in the Home Recording Sound Wizard, so I must be on the right track. Do you think this would work for my setup?
Amazon.com: Tascam US144 USB 2.0 Audio and MIDI Interface with digital Connection - Macintosh and Windows: Musical Instruments
Any suggestions that you think would work better for my setup?