If you want the background space above the header to match the blog set the body margin-top to what the space is & remove the "auto".
Code:
body {
margin: 20px auto;
padding: 0px;
font-family: verdana, arial, helvetica, sans-serif;
font-size: 62.5%;
color: #000000;
background: url(http://mademoiselleflo.com/images/background.gif) #EDC8EE fixed center top;
}
Try replacing the margin line with this line > margin-top: 50px;
Next arrange what you want for navigation and move them to the right column
admin > tools > layout boxes controller
when the right coluumn is how you would like set the left column to off
admin > config > layout srttings > Column Left Status - Global > set to "0"
this should get close to looking like your blog page