Try using Garage Band(assu

Try using Garage Band(assuming you have it-comes with the mac now). If you are not an advanced editor, this may be your key.

Once you import your audio into the track, find the podcasting effect and select Male or Femaie Narrator Noisy. You can then tweak if you would like, but depending on how bad the ambient sound is this may help without a lot of keyframming and tweaking.

Give it a shot!