When you update the website, change the link to the audio file to its real URL on your hosted site, not to its location on your local drive.
Example:
1. Create the site using WebEasy:
Put a link on a page similar to: (example only)
Link->Internet->File = C:\public\MultiMedia Files\MP3\myaudiofile.mp3
The site uploads fairly slowly.
2. Update the site using WebEasy
Change the link on the page to the MP3 file that is already uploaded, similar to: (example only)
Link->Internet->World Wide Web Site = http://www.myisp/mywebsite/myaudiofile.mp3
The site uploads much quicker this time as the MP3 is already on the site