Adding a tagline

I would like to add a tagline to a theme that doesn’t support taglines. I added the following to the header.php file: <p class=”tagline”>Website Design For Netherlands Non-profits and Charities</p

I placed it just after the header close: /h

That resulted in it being left-justified above the site title. I moved it down a little in the header.php file and it moved to below the menu.

I would like it to be centered below the site title and above the menu. There does not appear to be any position available in the file that will accomplish that,

Perhaps I somehow need to create a correctly positioned space for it? Can anyone suggest a path? Thanks.