Outside Sidebar

Moving the sidebar to the right of the header seems simple enough.

— Change #header-wrapper -- to width of #main-wrapper

— #header-wrapper -- float:left;

— Change #header-wrapper - margin:0 0 10px;

— Move <div id='sidebar-wrapper'> between <div id='header-wrapper'>'s closing </div> and <div id='content-wrapper'>
 ––This can easily be done with the Expand Widget Templates box unchecked

A post-change tweak to lower the sidebar a little.
—#sidebar-wrapper {
  width: 220px;
margin-top: 8px;

A change like this should be worked out on a test blog before moving the changes to a live one. Add the key elements and some content, and check everything to make sure it will work as desired.