Open style css. on line 36 change "border-bottom" to "border-top"
.wrap.menu { background:#FFFFFF; padding:0px 10px 0px 10px; width:940px; overflow:visible; border-top:solid 4px #D2D2D2;
Open header.php. Cut everything from line 36 to 42;
<div class="wrap menu">
<ul>
<?php fp_options('subscribe'); ?>
<li class="home-link<?php if ( is_home() ) { ?> current_page_item<?php } ?>"><a href="<?php echo get_settings('home'); ?>">Home</a></li>
<?php wp_list_pages('title_li=');?>
</ul>
</div><!-- /menu -->
- and past it at line 43, directly below
</div><!-- /header -->
That might give you a starting point.