go to Admin>alyout
check "Custom HTML in side panel on every page" and add:
<div class="addthis_toolbox addthis_floating_style addthis_counter_style" style="left:50px;top:50px;">
<a class="addthis_button_facebook_like" fb:like:layout="box_count"></a>
<a class="addthis_button_tweet" tw:count="vertical"></a>
<a class="addthis_button_google_plusone" g:plusone:size="tall"></a>
<a class="addthis_counter"></a>
</div>
and check "Custom HTML in <HEAD> section of every page" and add:
<script type="text/javascript" src="http://s7.addthis.com/js/250/addthis_widget.js#pubid=xa-502019d31de819c8"></script>
