I'll give you how to do it with graphedit this week-end as I'm not in my home at the mome,nt and do not have graphedit at the office (I don't know all the procedure by memory, I have to do it step by step myself while I describe it to you
).
But I'm quite sure that your MPEG is corrupted and nothing will handle it correctly.
New suggestion : open it in VDub (or VDub mod if it is a MPEG2), extract the audio and then frameserve tmpgenc for the video.
Other : do a little avs script that just load the mpeg and open it into tmpgenc. Then you can extract the audio by using the menu "File" -> "output to file" -> WAV
Other bis : the same but with a d2v project insteed of an avs script.