Fixing sidebars

Hi dear People,

I have three column theme…My two sidebars were on the right side, and I wanted to make one to be on the left, and other on the right, So I did this:

#sidebar
{
	padding: 0px 5px 10px 100px;
	margin: 0px 17px 0px 0px;
        margin-top: 0px;
	float:right;
        width: 188px;
	color:#F3F3F3;
	overflow: hidden;
	}

I put to one Sidebar to “float:right” and to another “float:left” ..at that point it seemed to me to be logick(not so experianced in css)
Was everything OK, but when I posted two sidebars went down, bellow post, I used “margin top:” but It didnt help as soon as I would put another post…

So, do You ppl have any suggestions on what should I do?!