You need to apply the float:right property to the whole sidebar div, rather than just the list (as that will just make the list float on the right 
within the sidebar div which isn't in any specific position. Similarly you should apply float:left to the 'content' div, so that they both float. Then you'll find that the ARTICLES/WRITING table is taking up the full width of the page, so you should also set the width of the 'content' div to something like 85% to give the sidebar some room (width: 85%).
Also, it's bad practice to add styling inline with the HTML. You should put your styling in a CSS file and add it above the <body> tag like so:
	Code:
	<head>
<link rel="stylesheet" href="~your css file here~.css" type="text/css" />
</head>