Header image does not work

Hi there,

first of all, thank you for the great theme.
I am new with drupal and I have some problems with the header image of MAYO.
First the image was not displayed at all.
I changed the page.tpl.php as following:

$header_style .= 'filter:;background: url(' . $base_path . '/' . $header_bg_file . ') repeat ';

now the image is displayed, but wrong:
also I sized it in Illustrator to the right size it is displays much too big.
And the image alignment is wrong.
If I choose top right -> please see the attached picture.

Please, can anybody help?