Any of you beautiful, intelligent people know the best way of doing this?

Recorded an interview on an Olympus digital VR before Christmas that I have to write up now. Turns out, as it was in a restaurant, the sound of what must be a coffee machine and the background music are kinda obscuring the voices. Then doesn't help that there's about four different voices and they don't have the clearest accents to decipher.

The voices are all there, and I can pick up a good bit of it, it's just I need to somehow isolate them/boost them and get rid of all the white noisey shite.

Is this easily done? Any improvement would be a help.