Hello Carol,
Doesn't your software allow you to take 'profiles' of your background noise? I took a sample from your mp3 (during the quiet bit at the start) and Auditions let me take a profile and then remove only the noise in the profile, it's attached for you to listen to.
I use the Art studio V3 preamp that Tekker mentions and it dramatiacally improved the results through my soundcard, I get the best results by setting record levels as high as I can without clipping.
good luck.
