To add a facebook like button just copy de code provided by the facebook inside your template.html
Something like this, as is in my site:
{ADMIN_MENU}
</div><!-- Begin IE7 support --><img src="images/spacer.gif" class="menuheight" alt="" /><!-- End IE7 support -->
<div style="float:right"><iframe src="http://www.facebook.com/plugins/like.php?href=http%3A%2F%2Fwww.fotopoint.com.br&layout=standard&show_faces=true&width=280&action=like&colorscheme=dark&height=80" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:280px; height:80px;" allowTransparency="true"></iframe></div>
<!--
<div style="float:right"><iframe src="http://www.facebook.com/plugins/likebox.php?href=http%3A%2F%2Fwww.facebook.com%2Fpages%2FFotopoint%2F173985332637949&width=220&colorscheme=dark&show_faces=false&stream=false&header=false&height=62" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:220px; height:62px;" allowTransparency="true"></iframe></div>
-->
<div class="clearer"></div>
{MESSAGE_BLOCK}
You can see it working on
http://www.fotopoint.com.brHope that helps you.