To change your usertitle, go to User Control Panel and click on Edit Your Details. Scroll down a bit and you'll see the Costum Usertitle section. Just enter the text you want to have it for your usertitle and click on Save Changes.
About the namechange, create a thread in the Staff Requests section, saying you want a namechnage. Include your new name in your post and mention Liz (add @ before her name to do that).