Hi,
You have two options:
1. Change this image:
templates/rhuk_milkyway/images/mw_joomla_logo.png
2. Edit your templates/rhuk_milkyway/css/template.css file and find this:
div#logo {
position: absolute;
left: 0;
top: 0;
float: left;
width: 298px;
height: 75px;
background: url(../images/mw_joomla_logo.png) 0 0 no-repeat;
margin-left: 30px;
margin-top: 25px;
}
And change the image path for another one.
Best regards,
Author