garage band input selection usb mic

I just bought a usb condensor mic and i'm trying to connect it to garageband (which i've never used). i selected the usb mic as the input source in the sound pane of system preferences. strong signal there, but no signal in garage band new track. when i open the "new track" window and select either mono 1, 2 or stereo, the input volume fader below is not "live", and therefore i can't up the input level of the usb mic??

Look under Preferences within GB

I believe that you'll also need to adjust your preferences under the file menu in GarageBand to select the USB mic as your input device.

cheers,
Jason