searchfunction in nextgen gallery

I’ve changed the search and function php in the the theme Responsive for a searchfunction in next gen gallery, but what do I have to do to let it work. Where can I insert the searchfunction? I have a page with a gallery, but see no possibilities to insert a searchfunction. I have the widges tab, and put in in the sidebar but when i activate that in the page, I lose one column.
What are the exact steps to put a searchbar above the gallery?