What they were trying to get at above with .AUP file is not the files you are after. The .AUP will allow Audacity to REDO what the original poster did years ago for editing the song, and I ASSUME generating the various label tracks. I have not loaded an AUP with labels tracks, but it may save them with it.
Reopen the .aup in Audacity. You will hopefully see the .mp3 editied so you can reexport it with the proper settings, be allowed to save all the label files tc.
Alan