changing the style size and including something in the header. help plz

[Sam1985]

Basically i created my own nav and logo that i want to use for the whole site.

1- How can i include a php file in the header.
if i go to edit template>header> and i want to include lets say mycustomheader.php(which is just a small 1024 by 200 header)

how should i write the code to include that page?

<?php
require('/home/httpd/thosts/something/httpdocs/mycustomheader.php');
?>

will that work? or i cant insert php into a header?

2- how do i change the width of a style to 1024 instead of 800?