That should work, but a 64 kbps MP3 is going to sound pretty rough... I'd personally just render to a WAV and use another program (i use iTunes) to convert it to an MP3. That way I can choose my bitrate, up to 320 kbps, which is almost indiscernible from the original WAV file. You get a pretty big file, but it sure sounds a lot better.

I'm a freak about sound quality, though. Once you hit the 192 kbps mark, most people can't tell the difference.