In this situation, I'd use an analogue chain to master, plus parallel processing, to beef it all up. Keep levels hot, but DO NOT tear any more of the audio with over hot levels, and... try get all the gain you want before and without the help of the limiter, in the analogue domain.
Also, if it's a joint stereo file you are in luck! If not, then scratch your head and nod in vain and leave it as is.. unfortunately.
Having spent years in radio, you learn to be an audio gymnast of sorts. And in radio, it's MP3's galore!!!!
Goodluck.. with whatever you end updoing.
Ciao'
FD