if you use the the File > Collect Files command, a new .aep will reference the copied files. If you need it to reference the copied file and it isn't just right click the audio file in the project window and select replace footage.
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.