How to change upload dir for custom plugin?

How to change upload dir for custom plugin?

I like to change the media upload directory for my custom plugin. Now i am testing with this in functions.php
 function custom_upload_directory( $args ) {
    // Check for our plugin pages
    if (($_GET['page']=="contender_add") || ($_GET['page']=="contender_edit")){
        $args['path'] = plugin_dir_path(__FILE__) . "uploads/test";
        $args['url']  = plugin_dir_url(__FILE__) . "uploads/test";
        $args['basedir'] = plugin_dir_path(__FILE__) . "uploads/test";
        $args['baseurl'] = plugin_dir_url(__FILE__) . "uploads/test";
    }
    return $args;
}

add_filter( 'upload_dir', 'custom_upload_directory' );
Also how do add my custom upload folder to the media uploader library tab?
Regards