Hi Bush,
It's good to see you want to change the look of the script as that would be a great start in learning. In fact I think you should do it yourself and I can of course give you some help, but I won't be able to reply very often.
In order to change the colors of you site, just edit the style.css file in the default template folder. In that style.css file all colors are defined, just play around with different colors and you will get a basic understanding of what each color does.
To change your logo, just replace the header_logo.gif file in the images folder in the default template folder by your own logo.
Make sure you back-up every file you edit, this way you won't loose the old default settings.
Cheers,
Vraxor