posts in category from horizontal navigation

I’ve spent some time researching the best way to do this and I’m coming up empty.

Here is a link to the development site:

http://creativeconundrum.com/mdsc/

Problem Statement:
Client would like to have posts within the Audio/Video Resources to display on hover.

Here is the code that I added to the theme’s functions.php. The SQL part of it has been tested in phpMyAdmin and it pulls exactly the data I’m looking for:

<?php
    function mdsc_avposts() {
	global $wpdb, $post_link;
	$sort_code = 'ORDER BY name ASC, post_date DESC';
	$the_output = '';

    $mdsc_post_list = (array)$wpdb->get_results("
        SELECT DISTINCT ID, post_title, post_date, post_name
        FROM wp_posts, wp_term_relationships, wp_term_taxonomy
        WHERE wp_posts.ID = wp_term_relationships.object_id
        AND wp_term_relationships.term_taxonomy_id = '13'
        AND wp_term_taxonomy.taxonomy = 'category'
        AND wp_posts.post_status = 'publish'
        AND wp_posts.post_type = 'post'	");

	if ( empty($mdsc_post_list) )
		return NULL;

	$mdsc_post_list = array_values($mdsc_post_list);

	$the_output .= '<ul>';
	foreach ($mdsc_post_list as $post_link) {
        $class = 'post-item post-item-' . $mdsc_post_list->ID;
        $current_post = get_the_ID();
        if ( isset($current_post) && $current_post && is_singular() && ($mdsc_post_list->ID == $current_post) )
            $class .=  ' current-post';
            $the_output .= '<li class="' . $class . '"><a class="" href="' . get_permalink($mdsc_post_list->ID) . '">' . apply_filters('the_title', $mdsc_post_list->post_title) . '</a></li>';
		$the_output .= '</li>';
	}
	$the_output .= '</ul>';
	echo $post_link;
}
?>

The updated functions.php did not make the theme break. 🙂

Can anyone who might be reading this give me a clue or advice on how to make the posts display under the Audio/Video Resources category link?