Find 'light.css' and locate '#header .module' and adjust the code 'margin-left' from 325px to something like 400px. You will need to tweak it to meet your needs but it's a start.
I have just been looking at your site and find that you have managed to change the logo to a much bigger size than the Afterburner. You have also managed to add the text below the logo.
I want to do the same as your self but find that the space in the afb-sprite.png is too small. How did you enlarge it?
I modified the light3.css (you have to modify the file who correspond to the colour you use). I put in comment the original #logo and added my own one.
/* Header */
/* #logo {width:288px;height:58px;background:url(../images/light3.png) 0 -272px no-repeat;display:block;margin:20px 15px;} */
#logo {width:353px;height:135px;background:url(../images/logo.png) no-repeat;display:block;margin:20px 15px;}
Now, this modification look for logo.png. For the text, it's included my logo.