Adding a date hack to popular posts

We want to be able to adjust the popular posts on the homepage so that it only shows the most popular posts within one week and not those from a few months ago.

The theme is Technical Speech.
Site is here.

The code we have at the moment is thus.

function popularPosts($options='') {
	$ns_options = array(
                    "count" => "3",
					"comments" => "1",
                    "before"  => "<div class=\"postblock\">",
                    "after" => "</div>",
					"show" => true,
					"place" => "content_col"
                   );

	$options = explode("&",$options);

	foreach ($options as $option) {
		$parts = explode("=",$option);
		$options[$parts[0]] = $parts[1];

	}

	if ($options['count']) {$ns_options['count'] = $options['count'];}
	if ($options['comments']) {$ns_options['comments'] = $options['comments'];}
	if ($options['before']) {$ns_options['before'] = $options['before'];}
	if ($options['after']) {$ns_options['after'] = $options['after'];}
	if ($options['show']) {$ns_options['show'] = $options['show'];}
	if ($options['place']) {$ns_options['place'] = $options['place'];}

	global $wpdb;
    $posts = $wpdb->get_results("SELECT comment_count, ID, post_title, post_excerpt, post_content FROM $wpdb->posts WHERE post_type='post' AND post_status = 'publish' AND comment_count >= ".$ns_options['comments']." ORDER BY comment_count DESC LIMIT 0 , ".$ns_options['count']);  

    foreach ($posts as $post) {
        setup_postdata($post);
	add_theme_support( 'post-thumbnails' );
        $id = $post->ID;
        $title = $post->post_title;
        $count = $post->comment_count;
		$excerpt = $post->post_excerpt;
		$content = $post->post_content;

		if (!$excerpt){
			$s = 1;
			if (strlen($content) > 325){
				for ($i = 325 ; $i <= 350 ; $i++){
					$temp_str = substr(strip_tags($content),$i,1);
					if ( $temp_str == " "){
						$excerpt = substr(strip_tags($content),0,$i) . " [...]";
						break;
					}
				}
			}else{
				$excerpt = strip_tags($content) . " [...]";
			}
		}

		if ($ns_options['place'] == 'content_col') {

           $popular .= $ns_options['before'].'<div class="postblockwrap"><h6><a href="' . get_permalink($id) . '" title="' . $title . '">' . $title . '</a></h6><p>'.$excerpt.'</p><a href="'.get_permalink($id).'" class="readmorelink">Read More</a></div>'.$ns_options['after']; 

		}elseif ($ns_options['place'] == 'content_row'){ 

			$popular .= '<div class="search_post"><div class="search_postdata"><a href="' . get_permalink($id) . '" title="' . $title . '">' . $title . '</a></div><p>'.$excerpt.'</p><div class="morelink" style="margin-bottom:5px;"><a href="'.get_permalink($id).'">Read More</a></div></div>'; 

		}elseif ($ns_options['place'] == 'sidebar'){

		   $popular .='<li><a href="'.get_permalink($id).'" title="'.$title.'">'.$title.'</a></li>';
		}

    }  

	if ($ns_options['show']==1) {echo $popular;} else {return $popular;}
}

As always, any help will be much appreciated – thanks.