I use sonic foundry sound forge, http://www.sonicfoundry.com/products...orgefamily.asp
I'm not sure if the price interests you as it's an expensive but very good one, not just for cutting out stuff, but it does a great job.
Try the demo and it should be able to open it and let you cut that part out.
You could always use a trial edition of Syntrillium's Cool Edit Pro. I've used it before and liked it very much.
Now, if you really want to incinerate that mp3, you could always decode it and import it into Digidesign's Pro Tools HD. Did I mention that the basic unit starts at $10,000 US?