plz help-i struggled in sidebar

If you see my blog the sidebar is absolutely left.
I want to lign it just after the ad which is near to sidebar.
how can i do that?

my stylesheet is mentioned below.
I tried plenty of times but nothing works.
please help

{
padding: 0;
margin: 0;
align: left;
}

body
{
font-size: 76%;
font-family: ‘Trebuchet MS’, Arial, Verdana, Sans-Serif;
align: left
}

hr
{
display: none;
}

#page
{
width: 100%;
margin: 0 auto;
border: none;
background-color: white;
align: left
}

#wrapper
{
width: 300;
margin: 0 auto;
}

#content
{
float: left;
width: 50%;
}

.post
{

align :left
margin-bottom: 20px;
color: black;
padding-left: 5px;
padding-right: 5px;
font-size: 1.1em;
}

h2
{
font-size: 1.6em;
border-bottom: 1px solid black;
float: left;
}

h2 a:hover, h2 a:visited, h2 a
{
text-decoration: none;
color: black;
float: left;
}

.entry
{
margin-top: 10px;
margin-bottom: 15px;
}

.postmetadata
{
padding: 2px;
font-size: 0.8em;
border-top: 1px solid #778899;
}

.postmetadata a
{
color: #778899;
}

.post p
{
line-height: 1.4em;
margin-bottom: 1em;
}

blockquote
{
margin: 1em 1.5em;
padding: 1em 1.5em;
border: 1px solid #778899;
background: #d3d3d3;
}

.post li
{
margin-left: 10px;
}

.post ul
{
list-style-type: disc;
margin-bottom: 10px;
align:left;
}

acronym, abbr, span
{
cursor: help;
}

acronym, abbr
{
border-bottom: 1px dashed #778899;
}

blockquote cite
{
margin: 5px 0 0;
display: block;
}

.center
{
text-align: center;
}

a img
{
border: black;
}

h3
{
margin-top: 1em;
margin-bottom: 1em;
font-size: 1.4em;
}

h4
{
margin-top: 1.2em;
font-size: 1.2em;
}

h5
{
margin-top: 1em;
font-size: 1em;
}

a
{
color: #778899;
}

.navigation
{
display: block;
margin-top: 10px;
margin-bottom: 40px;
}

.alignleft
{
float: left;
text-align: left;
width: 100%;
}

.alignright
{
float: right;
text-align: right;
width: 100%
}

ol.commentlist
{
width: 90%;
margin: 0 auto;
}

ol.commentlist li
{
margin-bottom: 1.5em;
border: 1px solid #778899;
padding: 5px;
background-color: #d3d3d3;
}

ol.commentlist li.alt
{
background-color: #d3d3d3;
}

ol.commentlist a
{
color: #778899;
}

small.commentmetadata
{
font-size: 0.8em;
margin-bottom: 1em;
display: block;
}

#header
{
margin-bottom: 10px;
margin-top: 10px;
text-align: centre;
padding: 5px;
}

#sidebar
{
float: right;
width: 225;
padding: 2px;
text-align: left;
}

#sidebar ul
{
list-style: none;
margin-bottom: 20px;
align: left
}

#sidebar ul ul
{
list-style-type: circle;
margin-left: 20px;
align:left
}

#sidebar ul ul ul
{
margin-bottom: 0;
}

#sidebar ul h2
{
border-bottom: 1px solid #778899;
border-top: 1px solid #778899;
font-size: 1.2em;
font-weight: normal;
padding: 2px;
margin-bottom: 5px;
}

#footer
{
padding: 5px;
clear: both;
text-align: left;
}

#sidebar_r
{
float: right;
width: 140px;
padding: 3px;
text-align: left;
}

#sidebar_l
{
float: left;
width: 160px;
}

.description
{
border-bottom: 100px;
}

#ad_hf
{
float : centre;
padding-top: 10px;
padding-bottom: 10px;
background-color: white;
}

#search
{
padding-left: 20px;
background-color: #ebebeb;
}