Remixing without stems -- Frustrating!

i'm aware this is how bootlegs are made, but i was recently sent a 12 min. WAV file to remix that was recorded all in one go. i've tried EQ'ing it to hell, but i'm not getting anywhere with it. i've been getting a bit discouraged to finish it up, but it's a paid gig with high profile connections, so i'd like to do a good job. any tips for plugins or simple techniques i can use? i use ableton, but i can get access to Logic or ProTools at a friend's studio.

thanks mucho.