I always check my site on other people's computers. I have a wide screen flat panel so both the sizing of a website and colours are different from others especially those with older models.
I would look at some of the other sites to get an idea of design and structure. It will take you time but with each attempt you get better. My site is no where near being correct or exactly what I want but I'm working on it and am happy with the progress.
I would definately fix the size of your page and banners. I do like your header so maybe increase that to fit your page. Where it sits right now just looks like another advertisement.
Good luck!
