How do I remove 'customheader-holder' area?

Hi, I am doing this website: http://www.hauora.com/ and want to remove the bit between the dark coloured header and the intro bit (e nga mana....). It is just empty space. I used the Firebug add on for Firefox and I think the div is called customheader-holder. How do i get rid of it or make it smaller?

Thanks in advance
Brigham