I haven't seen such an awful bevelled button header graphic since my degree in '99....seriously, that's horrible. If you like that highlight effect, then do a gradiant fill and mirror, don't use a button tool....
You shouldn't hard code anything for a specific browser. If you're serious about doing the website, it should work for everyone. It's a pain in the arse, but that's how it works.
What resolution do you design at? 'Cause those menu links across the top are massive at 1024x768, so they must be hhhhuuuugggeeee at 800x600.....They look big at 1920x1200 (and I'm still getting that background too narrow for my screen issue).
Hope this helps.
And I can't believe no-one has asked, but what the hell is Korfball?