I have an unregistered boxed software of BIAS's Sound Soap 2. This is a super easy way to get noise reduction without having to mess with Soundtrack Pro. There are plenty of tutorials on how easy it is, but here is the one from the manufacturer's website:
http://www.bias-inc.com/downloads/videos/soundSoap2/
$100 including the shipping to anywhere in the US
http://www.bias-inc.com/downloads/videos/soundSoap2/
$100 including the shipping to anywhere in the US