The easiest way would be to upload your image to /forum/images/misc/YOURLOGO.GIF. Then go into style vars on your skin and edit the options that says title image with the URL to the image you just uploaded.
Or, you can go into your header template and code it in yourself. ie. <img src="URL OF LOGO"> something like that.
btw, i clicked your example link because I didn't read through all the way... quite interesting lol