Custom Editing theme

Hey, I would like to custom edit my theme. I was wondering if you could give me the correct html to help me do this or point me in the right direction. I basically want my page to look like this.. http://www.flickr.com/photos/92334073@N06/9906226343/ I would like to know the dimensions of the background, how I can change it inc removing the grey header. If it's possible to change the menu bar as shown in the photo, not just the colour but the style. And how I would place the logo in the middle and position the tagline. Sorry I'm rubbish with HTML. http://www.thelostlondoner.com