LizzyLu are you using Disqus for your comments? If not, you may want to look into that.
Editing Gallery.php will be the key to get all you guys up and running. Be careful though, when NextGen releases and update, remember to back up gallery.php!
Hey guys,
Adding Facebook like and tweet buttons to the individual images isnt THAT painful.
If you have the latest wordpress, install JetPack, it should be prompting you to install it at this point.
Set up your sharedaddy settings in jetpack (select facebook, twitter etc)
Then go to edit your plugin and edit nextgen-gallery/view/gallery.php
Find the spot you would like your buttons to appear on the individual post page and add <?php echo sharing_display();?> the shortcode for sharedaddy and your share buttons will appear!
Good luck!