Add this before the content:
<?php
$images = get_children( array('post_parent' => $post->ID, 'post_type' => 'attachment', 'post_mime_type' => 'image', 'orderby' => 'menu_order', 'order' => 'ASC', 'numberposts' => 999));
if ($images) :
$total_images = count($images);
$image = array_shift($images);
$image_img_tag = wp_get_attachment_image($image->ID, 'thumbnail'); ?>
and you can add this in place where you want your first image to display:
<div class="thumbnail">
<a href="<?php the_permalink();?>"><?php echo $image_img_tag;?></a>
</div>
Recommendation before anything would be for you to upgrade your WordPress you're using outdated:
<meta name="generator" content="WordPress 2.8.5" />
Current version is 3.0.4 :-)
Emil