Expanding The Width Of Twenty Ten

I’m working in a child theme of twenty ten. I want to expand the width from 940 pixels to 1100 pixels.
In doing this I want to also expand the header image to the same width as the page, 1100px. And the content area to also be 1100px with no padding or borders.
I can achieve all this when the page width is 940px wide but when I expand the width of the page
the header doesn’t centre and the content area has padding at each side.
Here is the code I targeted.
Style.css
#wrapper {
margin: 0 auto;
width: 1100px;
}
and header to 1100px
functions.php
‘width’ => apply_filters( ‘twentyten_header_image_width’, 1100 ),
‘height’ => apply_filters( ‘twentyten_header_image_height’, 180 ),
A new 1100px wide header image was inserted.
And the content area
Style.css
.one-column #content {
margin: 0 auto;
width: 1020px;
}
My site- derekbrennan.co.uk
Thanks.