This is my current header code with the line you said to add. I made a 10x10 transparent .png and uploaded it to the themes /image folder and wrote in the code below. It still doesnt seem to be working...
/* Header
-------------------------------------------------------------- */
#header{background-color:transparent;position:relative;height:200px;border-top:8px solid #888;}
#header_extras{position:absolute;right:30px;}
#header_extras_inner{margin-top:-8px;overflow:hidden;padding:2px 10px;}
.header_extras { background-image:url("images/transparentbg.png") !important; }
.header_links{float:left;font-size:9px;padding:2px 10px 2px 0;}
.header_links a,.header_links a:hover{color:#eee;}
.header_links ul{list-style:none;padding:0;margin:0;}
.header_links li{float:left;padding-left:10px;}
.header_links li ul{float:right;margin-right:0px;}
.header_social{float:left;padding:0 5px;}
.header_social .social_icon{float:left;padding:0 2px;}
.header_social img{vertical-align:bottom;}
.header_text{float:left;font-size:10px;color:#eee;padding:2px 10px;}
.has_header_social.has_header_text #header_extras,.has_header_links.has_header_text #header_extras{}
.logo{position:absolute;Bottom:50px;line-height:85px;}
.logo a:hover{text-decoration:none;}