Create one or more new panes view under Audio for your audio files, and under Video for your video.
In the view customize dialog, click Set rules for file display... and configure a Filename (path) rule that starts with the full path to your nas drive. Example:
\\nas\path\to\ripped cds
this will limit the results for this view to only files whose path begins what that folder path.
Do likewise for other views. This will yield new views under the desired media types.
You might also consider create a single view / media type, whose first column allows you to select which type of media you want to use. You'd do this by using either an expression or search list column. Ask if you want more help here.
Note: the view will inherit the limitation of the file types shown based upon the top-level media section (eg. Audio, Video, etc.) where you've placed the view. A view can override this and show any media types.
See:
http://yabb.jriver.com/interact/index.php?topic=68960.0
