To create custom templates for Nextgen-Galleryview:
1) Create a sub-folder named "nggallery" in the folder of your WordPress theme, i.e. /wp-content/themes/twentytwelve/nggallery/
2) Copy the file /wp-content/plugins/nextgen-galleryview2/view/gallery-galleryview.php to the folder you created in Step 1.
3) If you want to make any changes to the default behavior of Galleryview, edit the copy of gallery-galleryview.php in your theme's /nggallery/ folder instead of the one in the plugin's /view/ folder; that way your changes aren't lost when upgrading the plugin.
4) Make additional copies of gallery-galleryview.php in your theme's /nggallery/ folder, renaming them with unique identifiers before the .php extension, i.e. gallery-galleryview-template2.php
5) Edit gallery-galleryview-template2.php. There are 30 different options for controlling the look and behavior of Galleryview.
6) When inserting the Nextgen shortcode, use the new Galleryview template name. I.e. instead of [nggallery id=1 template="galleryview"], you would use [nggallery id=1 template="galleryview-template2"]
After posting this, I see from another thread you have this figured out now, but maybe this will be useful to someone.