Is it a stereo or a mono track? If it's a mono track there's not going to be a lot you can do *neatly*, because they are all on one track, and one cannot neatly and cleanly "unscramble an egg". There are some limited "sloppy" things you can do, though. If you can get a hold of a used copy (because they are no longer sold new) of either Elemental Audio's Neodynum or Roger Nichols Digital's Dynamizer, they let you compress and expand tracks by volume "zones".
You could also try Adobe Audition's spectral editor to try and remove as much vocal from one copy of the track as possible while leaving the other stuff in there, and then add that back to a copy of the full, original track to bring up the other stuff while leaving the vocal the same volume.
If you're kind of a rookie to this kind of stuff, though, both tools and techniques will have quite a steep learning and practice curve to them. Even for the experienced, the procedures are not easy, and for anyone, neither of them will be perfect. There's no such thing as an Easy Button for this problem.
If it's a stereo track, and the vocals are panned center with most everything else panned off of cente, you could use a mid-side processor plug (Voxengo has a free one) to temporarily put the center stuff on one channel and the L&R stuff on another channel. Then you can adjust the volumes of them separately and re-integrate them into there original stereo panning.
G.
