As it's a WordPress site you'll need to edit your header file, which is likely called header.php.

Upload the image to your server, the same directory as your theme resides is as good a place as any. Then edit the header file to insert the image.

You may also want to surround it with div or span tags and make a corresponding entry in the stylesheet in order to position it precisely where you want it.

Hope this helps

Bill

Thanks. I'm messing with it now and trying to figure out how to get it in the right place without pushing the logo image down.