Spike,
After you update the Open Graph description, make sure you're using Facebook's URL debug tool to check what it sees:
developers.facebook.com/tools/debug
Changes on your site can take a few days to appear when you click the Like or Send button, if that's how you're testing. The Debug Tools has (generally) immediate results.
If that is how your testing and it's still not working, let me know and we can look into it more. If there's a specific page other than the homepage with the problem, let us know that too.
Thanks,
Alex