Trying to limit query to X amount of days...how?

[SBlueman]

What do I need to change in these bits of code to make it where the "Most Read" and "Most Commented" so that the modules only list the top articles in the last "X" amount of days?

PHP Code:

if (in_array('mostread', $af_modules))
    {
        $row = 0;
        $af_mrpp = $vbulletin->options[af_mrpp];
        $threads = $db->query_read("
            SELECT thread.threadid,thread.title AS threadtitle
            FROM " . TABLE_PREFIX . "thread AS thread
            LEFT JOIN " . TABLE_PREFIX . "post AS post
                ON (post.postid = thread.firstpostid)
            WHERE thread.forumid IN ($forumids)
            $visiblethreads $authorids $condition
            ORDER BY views DESC
            LIMIT 0, $af_mrpp");
        while($thread = $db->fetch_array($threads))
        {
            $row++;
            $thread = process_thread_array($thread, $lastread, $foruminfo['allowicons']);
            $thread[threadtitle] = substr($thread[threadtitle], 0, $vbulletin->options[af_maxtitle]);
            eval('$a_most_read .= "' . fetch_template('af_articlesmallbit') . '";');
        }
    } 


PHP Code:

    if (in_array('mostcommented', $af_modules))
    {
        $row = 0;
        $af_mcpp = $vbulletin->options[af_mcpp];
        $threads = $db->query_read("
            SELECT thread.threadid,thread.title AS threadtitle
            FROM " . TABLE_PREFIX . "thread AS thread
            LEFT JOIN " . TABLE_PREFIX . "post AS post
                ON (post.postid = thread.firstpostid)
            WHERE thread.forumid IN ($forumids)
            $visiblethreads $authorids $condition
            ORDER BY replycount DESC
            LIMIT 0, $af_mcpp");
        while($thread = $db->fetch_array($threads))
        {