First, this thread will get locked because it has nothing to do with hardware. So before that:
Honestly, I use QuickTime Pro on the Mac. It's actually amazingly powerful in its simplicity. I play the sound until the point between clips. Then hold down shift to select everything from there back to the start of the file while dragging the cue slider. Cut, New File, Paste, Export as WAV. With the right tools, it's mostly scriptable with AppleScript.
May not help you, but that's how I do it.