Try doing this:
Open your System Preferences and select your Spotlight Pref's. Then click on the Privacy tab.
Drag an external disk icon onto the privacy tab.
Close the pref's and do something else for about 10 minutes.
Then go back to the Spotlight privacy tab and remove the drive from the list.
That should make Spotlight index that drive and hopefully it will then show in a search.
If that doesn't help, there is this little app that might work.
http://homepage.mac.com/superpixel/highlight/There are also terminal commands that force Spotlight to index but it is only a temporary fix.
