Here are the three main elements I styled to push things around. First, lock the logo into the top-left corner...
Code:
#logo {
position: absolute;
top: 10px;
left: 10px;
}
Next, move the tagline over to the right...
Code:
#taglineWrapper { text-align: right; }
Then, to answer your request, push the left column down to leave room for the logo. In my case, the top element in my left column is the cart summary. You'll have to decide which element to style based on your layout...
Code:
#cartsummaryHeading {
margin-top: 200px;
}
Finally, to let the whole page stay the desired width, but centered in any wider browser window...
Code:
#mainWrapper {
margin: auto;
top: 0px;
left: 0px;
... other styles here ... }
HTH
Rob