Right Sidebar Help For Rainbow Trance 1.0!!

I’m trying to remove the Advertisement tab or place my own Ad there. Right now it just says advertisement with a blank picture saying “Ad Space”. My sidebar.php file looks like this…

<!– Sidebar –>
<div class=”sidebar”>

<h3>Pages</h3>

<?php wp_list_pages(‘title_li=’); ?>

<h3>Archives</h3>

<?php wp_get_archives(‘type=monthly’); ?>

<?php if ( !function_exists(‘dynamic_sidebar’) || !dynamic_sidebar(1) ) : ?>

<?php endif; ?>

</div>
<!– Sidebar –>
——————————————————–
Is there a way to edit this so I change the advertisement bar or could I hide it somehow? Is there a way to do it through the style sheet using css??? Please help. I’ve been messing around for hours now and can’t figure it out. The theme does not come with a settings option. I still want to keep the right sidebar, just remove the advertisement/add my own.