twenty eleven sidebar in new page tempalte

add_filter('body_class', 'allow_sidebar_on_template', 20, 2);
function allow_sidebar_on_template($wp_classes, $extra_classes) {

if( is_page_template( 'yourtemplatefilename.php' ) ) : // Filter the body classes
    if (!in_array('singular', $wp_classes)) : continue;
    else:
      foreach($wp_classes as $key => $value) {
      if ($value == 'singular') unset($wp_classes[$key]);
      }
    endif;
endif;
return array_merge($wp_classes, (array) $extra_classes);
}