Modifying teaser node comment links
This specifically answers your question on how to override the comment links. The important part is using the value of $vars['comment_count'] to add the count into your altered link title.

function YOURTHEME_preprocess_node(&amp;$vars) {
    if(!empty($vars['content']['links']['comment'])){
        // Get rid of other comment link with counts
        $vars['content']['links']['comment']['#links']['comment-comments'] = array();
        // Override the title of the add a comment title displaying a count
        if($vars['comment_count'] &gt; 0)
            $vars['content']['links']['comment']['#links']['comment-add']['title'] = 'Comments ('.$vars['comment_count'].')';
        else
            $vars['content']['links']['comment']['#links']['comment-add']['title'] = 'Comments';
    }
}