Audio Extraction?

I am working on a video and the Audio is far to quiet, I asked the client if they had any Audio files separate from the video files and this was the reply.
"The microphones are tied to the different audio channels of the footage. Typically one will be ambient and another will be a microphone. You should be able to separate them and adjust the microphone."
Usually I will have separate Audio files to work with, so this is kind of new to me. Anyone help me out on this one? I am using Adobe Premiere CS5.5

via Video Editing Forums: Digital Director – Adobe Premiere, Premiere Elements, and After Effects http://www.videoforums.co.uk/adobe-premiere-premiere-elements-after-effects/43029-audio-extraction.html