¿Agregar botón para seguir en Facebook en mi sitio web?

<style>
#fanback{display:none;background:url(https://sites.google.com/site/terrenoblogger/imagenes/bg.png);width:100%;height:100%;position:fixed;top:0;left:0;z-index:99999;}#fan-exit{width:100%;height:100%}#fanbox{background:white;width:420px;height:270x;position:absolute;top:50%;left:50%;-webkit-box-shadow:inset 0 0 50px 0 #939393;-moz-box-shadow:inset 0 0 50px 0 #939393;box-shadow:inset 0 0 50px 0 #939393;-webkit-border-radius:5px;-moz-border-radius:5px;border-radius:5px;margin:-135px 0 0 -210px;}#fanclose{float:right;cursor:pointer;background:url(https://sites.google.com/site/terrenoblogger/imagenes/fanclose.png) repeat;height:15px;padding:20px;position:relative;padding-right:40px;margin-top:-20px;margin-right:-22px;}.remove-borda{height:1px;width:366px;margin:0 auto;background:#F3F3F3;margin-top:16px;position:relative;margin-left:20px;}
</style>
<script type="text/javascript">
jQuery.cookie=function(key,value,options){

if(arguments.length>1&&String(value)!=="[object Object]"){options=jQuery.extend({},options);

if(value===null||value===undefined){options.expires=-1;}

if(typeof options.expires==='number'){var days=options.expires,t=options.expires=new Date();t.setDate(t.getDate()+ days);}

value=String(value);

return(document.cookie=[
encodeURIComponent(key),'=',
options.raw?value:encodeURIComponent(value),
options.expires?'; expires='+ options.expires.toUTCString():'',
options.path?'; path='+ options.path:'',
options.domain?'; domain='+ options.domain:'',
options.secure?'; secure':''].join(''));}

options=value||{};
var result,decode=options.raw?function(s){
return s;}:decodeURIComponent;return(result=new RegExp('(?:^|; )'+ encodeURIComponent(key)+'=([^;]*)').exec(document.cookie))?decode(result[1]):null;};
</script>

<script type="text/javascript">
jQuery(document).ready(function($){if($.cookie('popup_user_login')!='yes'){
$('#fanback').delay(100).fadeIn('medium');
$('#fanclose, #fan-exit').click(function(){
$('#fanback').stop().fadeOut('medium')})}
$.cookie('popup_user_login','yes',{path:'/',expires:30})});
</script>
<div id="fanback">
<div id="fan-exit"></div>
<div id="fanbox">
<div id="fanclose"></div>
<div class="remove-borda"></div>
<!-- Facebook -->
<iframe allowtransparency="true" frameborder="0" scrolling="no" src="//www.facebook.com/plugins/likebox.php?href=http://facebook.com/ID_PAGINA&amp;width=402&amp;height=255&amp;colorscheme=light&amp;show_faces=true&amp;border_color=%23E2E2E2&amp;stream=false&amp;header=false" style="border: none; height: 230px; margin-left: 8px; margin-top: -19px; overflow: hidden; width: 402px;"></iframe></div>
</div>