This will change the text of the button:
function my_gwolle_gb_button($html) {
$old = '» Write a new entry.';
$new = 'New String';
$html = str_replace( $old, $new, $html );
//var_dump($html);
return $html;
}
add_filter( 'gwolle_gb_button', 'my_gwolle_gb_button' );
function my_gwolle_gb_write($html) {
$old = 'Guestbook entry';
$new = 'New String';
$html = str_replace( $old, $new, $html );
$old = '\*';
$new = '';
$html = str_replace( $old, $new, $html );
//var_dump($html);
return $html;
}
add_filter( 'gwolle_gb_write', 'my_gwolle_gb_write' );
Not sure about this last function where the * gets replaced. Please test.
You can place this code in functions.php of your theme or in your own plugin.
I will think about the feature for the widget.