.main_content{
  float:left;
  width:645px;
  padding:5px 0;
}
.main_content .col3{
	padding:0 2px;
	width:980px;
}
.main_content .col2{
	margin:0 10px;
}
.extra_content{
	padding:5px 0px 5px 20px;
	float:left;
	clear:right;
	width:300px;
}
	.extra_content #ad300x250box{
		width:300px;
		height:250px;
		overflow:hidden;
		background:#97989c;
	}