Change the Top Join Link

I am running Dolphin 6.1 and would like to change the join link ("Join Now for Free") at the top of my website at Nudei.com so that it loads an external website.

Which file do I need to modify? I looked at _header.html, but the join link seems to be further down the page.

It's kind of not where you would think to look.  Go to your templates, uni, scripts folder and open functions.php.  About halfway down look for the line starting with

$ret .= '<div class="join_now">'

and you'll see the href. 

All the best.