I've already found some new promising documentation:
http://www.fanjita.org/serendipity/archives/22-Instrument-Tuner-Audio-Input-Stage.html
is a post detailing a transistor amplifier circuit and
http://www.fanjita.org/serendipity/archives/23-Instrument-Tuner-Zero-Crossing-analysis.html
is a follow-up post on using that circuit in conjunction with ATmega328 (Arduino) chips' built in analog comparator to determine the frequency of a sine wave.
Does this look like a potential solution to my problem? I will try and digest the info and then try the circuit + code for myself soon.