Well, before you do anything at all in there on the code, save yourself a copy of the page, or else start up a new one with all the same characteristics, but just save it as a trial page so things don't get mixed or lost.
Now looking in there, it looks to me as if you can make some changes in the top part of the menu code.For instance:
var StartTop=1; // Menu offset x coordinate
var StartLeft=1; // Menu offset y coordinate
I reckon if you do something to those two numbers "1" you will shift the menu down from the top of the page and over from the left.
var MenuCentered='left'; // Menu horizontal position 'left', 'center' or 'right'
var MenuVerticalCentered='top'; // Menu vertical position 'top', 'middle','bottom' or static
Then again you could maybe try out changing the position in the top line here... try putting 'center'
Don't know if it will help to change the vertical center though which will possibly be changed when you alter the numbers in the previous snippet I included here. Those numbers refer to pixels so check out how high your header image is and try a number just slightly bigger...I think your header is about 142 px, so maybe that number or a little more.
Then let us know how things have worked out.