Nice to read you here!
i'm reading about the QT and i found that it only have digital output (like a button).
Maybe you can read this threads here at the arduino forums about theremins:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1168942948
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1194716896/6
and this one about use two arduino pins to made a capacitive sensor:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1171076259
good luck!
zea