CSS- cant make the 2 sidebars have a space…. tried margin & padding

Blog is at https://letterstobreathe.com and I am playing around with the sidebars, and cant get them to have a space between them. They both use the float left and the content uses float right.

The margins only add space in the sidebar itself (extends the image background out that much more)

there has to be a way to get the two sidebars to have a space between them…. i even tried adding clear:left to the one on the right and it just made it move down below the one on the left…

#content{
	float:right;
	width:540px;
}
#sidebar_right{
	float:left;
	width:180px;
	padding:7px 6px 10px 10px;
	background: url(images/postback.jpg);
	border:1px solid #808080;
	-moz-border-radius: 4px;
	-webkit-border-radius: 4px;
	border-radius: 4px;
}
#sidebar{
	float:left;
	width:180px;
	background: url(images/postback.jpg);
	border:1px solid #808080;
	-moz-border-radius: 4px;
	-webkit-border-radius: 4px;
	border-radius: 4px;
	padding:7px 6px 10px 10px;
}