Nofollow link for plugin links

In http://www.onlineincomestartup.com/drive-traffic-to-your-website/ , In the author bio that shows up inside each posts,

I need to make all the links except Google plus, a no follow for SEO purposes.I am using a plugin called WP about author.I guess I need to make changes to the following code.But I’m not that good in editing codes.someone please help.thanks

// Generate social icons
function wp_about_author_get_social_links($wp_about_author_settings){
    $content="";
    $socials = wp_about_author_get_socials();
    foreach($socials as $social_key=>$social){
        if (get_the_author_meta($social_key)){
            if(isset($wp_about_author_settings['wp_author_social_images']) && $wp_about_author_settings['wp_author_social_images']){
                $content .= "<a class='wpa-social-icons' rel="nofollow" href='".str_replace('%%username%%', get_the_author_meta($social_key), $social['link'])."'><img src='". $social['icon']."' alt='".$social['title']."'/></a>";
            } else {
                if($content != "")
                    $content .= apply_filters( 'wp_about_author_separator', " - ");
                $content .= "<a href='".str_replace('%%username%%', get_the_author_meta($social_key), $social['link'])."'>".$social['title']."</a>";
            }
        }
    }
    return $content;
}

function wp_about_author_get_socials() {
    $socials = array();
    $socials['twitter'] = array('title'=>'Twitter', 'link'=>'http://www.twitter.com/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/twitter.png');
    $socials['facebook'] = array('title'=>'Facebook', 'link'=>'http://www.facebook.com/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/facebook.png');
    $socials['linkedin'] = array('title'=>'LinkedIn', 'link'=>'http://www.linkedin.com/in/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/linkedin.png');
    $socials['pinterest'] = array('title'=>'Pinterest', 'link'=>'http://www.pinterest.com/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/pinterest.png');
    $socials['googleplus'] = array('title'=>'Google Plus', 'link'=>'https://plus.google.com/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/googleplus.png');
    $socials['digg'] = array('title'=>'Digg', 'link'=>'http://www.digg.com/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/digg.png');
    $socials['flickr'] = array('title'=>'Flickr', 'link'=>'http://www.flickr.com/people/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/flickr.png');
    $socials['stumbleupon'] = array('title'=>'StumbleUpon', 'link'=>'http://www.stumbleupon.com/stumbler/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/stumbleupon.png');
    $socials['youtube'] = array('title'=>'YouTube', 'link'=>'http://www.youtube.com/user/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/youtube.png');
    $socials['yelp'] = array('title'=>'Yelp', 'link'=>'http://www.yelp.com/user_details?userid=%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/yelp.png');
    $socials['reddit'] = array('title'=>'Reddit', 'link'=>'http://www.reddit.com/user/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/reddit.png');
    $socials['delicious'] = array('title'=>'Delicious', 'link'=>'http://www.delicious.com/%%username%%', 'icon'=> WPAUTHORURL_URL .'/images/delicious.png');
    return apply_filters( 'wp_about_author_get_socials', $socials );
}