Site e-mail settings on install

Can someone tell me where to go to change the e-mail settings that let you know who has joined your site? These are the three that are set up during the installation of dolphin. I had a company do a install for me and they messed it up by making a e-mail address for me. I recently made a new e-mail address and I want all my stuff that has to do with my site come to this new e-mail address. I do not want to wipe the site since I have already configured a lot of it.

open and edit in inc/header.inc.php