Grid Focus Theme – Button in top nav bar

I have created a subdomain and I would like to add in a MAIN button in the top nav bar that takes me to my main site. I know I have to do it in the navigation strip php. But I don’t know what the code should look like. Can anybody help me out with that?

I am using the Grid Focus theme, and this is a link to my blog. I would like to put the MAIN button next to the SUBSCRIBE one.

This is the php

<?php
/**
 *	@package WordPress
 *	@subpackage Grid_Focus
 */
?>
<div class="navStripWrapper">

	<ul class="nav fix">
		<li><a href="<?php echo get_settings('home'); ?>/" title="HOME">HOME<br /><span>Frontpage</span></a></li>
		<li><a id="triggerCatID" href="#" title="Show categories">Browse<br /><span>By topic</span></a></li>
		<li class="last"><a href="<?php bloginfo('rss2_url'); ?>" title="Subscribe to the main feed via RSS">Subscribe<br /><span>RSS feed</span></a></li>
		<li id="searchBar1" class="searchField">
			<div>
				<form method="get" id="searchForm1" action="<?php bloginfo('home'); ?>/">
				<span><input type="text" value="Search the archives..." onfocus="if (this.value == 'Search the archives...') {this.value = '';}" onblur="if (this.value == '') {this.value = 'Search the archives...';}" name="s" id="s1" /></span>
				</form>
			</div>
		</li>
	</ul>

	<div id="headerStrip" class="toggleCategories fix" style="display: none;">
		<ul class="fix">
		<?php wp_list_cats('sort_column=name&amp;optioncount=0&amp;exclude=10, 15'); ?>
		</ul>
	</div>

</div>