Help with audio filters

I am working in final cut express hd and I am trying to seperate background noise from a person speaking in a clip. Is one filter better than another. The noise is just of a crowded room. I had the person hooked up to a mic but it still picked up a bunch of extra noise--is there any way to reduce that noise?

I've been messing around with different filters for a couple of hours but if anyone has any specific suggestions it would be much appreciated!