Add a link to what? if you mean a html link the like this: <a href="http://www.mysite.com">My Site</a> so it would look like this:
PHP Code:
<if condition="THIS_SCRIPT == 'index' AND is_member_of($bbuserinfo,1)"><div id="floatdiv" style="
position:absolute;
width:200px;height:50px;left:0px;top:0px;
padding:16px;background:#FFFFFF;
border:2px double #2266AA">
<a href="http://www.mysite.com">My Site</a>
</div> </if>