You just need to change
/wp-content/plugins/achievements/includes/templates/members/single/achievements.php
/wp-content/plugins/achievements/includes/templates/achievements/index.php
/wp-content/plugins/achievements/includes/templates/achievements/single/home.php
I think, so that
<div id="sidebar-squeeze"><br />
<div id="main-column">
comes immediately after the content and padder divs at the top of the files and
</div><!-- .main column --><br />
<div id="side-bar" role="complementary"><br />
<?php get_sidebar() ?><br />
</div> <!-- #sidebar --><br />
</div><br />
<!-- #sidebar-squeeze -->
come before the end padder and content divs at the bottom of the files.
