This will be my first post here, been lurking for roughly a year now on these forums, which has helped me alot, so it's time i'll start to try and contribute
<font color='"#FF0000"'>margin: 405px 12px;
The reason for your page being this tall is the style of your rightside div, is the part in red. U have a margin of 405px applied to the top and bottom. Try setting it to margin: 405px 12px 0 12px; that way it should still have 12 pixels margin on both sides, and only 405 pixels at the top. Also the min-height: 800px; is creating excess page height, so u could try to reduce the value of that, or even remove it completely.
Not sure what u meant by centering the focus when the page loads, the page looks quite centered to me.