Web design (CSS, HTML) Options

[Qrbrrbl]

Hey guys.

I'm attempting to build a website for my badminton club, but for some reason the header and links bar isn't displaying correctly in some versions of IE. I'm completely new at this and I've been writing the code based off tutorials so I don't really know what I'm doing. Can anyone help?

The site is currently at http://www.hooduk.plus.com/

It seems to render correctly on the following:
FireFox & IE9 on Win 7
Dolphin HD on Android.

And has trouble on the following:
IE7 & 8 on Win XP
IE8 on Win 7

[Qrbrrbl]

Ok so i've come back to this after a long while and updated a lot. The main issue seems to be that IE8 and below mostly ignore the CSS, so the top banner and the nav bar dont display properly, along with the content divs further down that split the page in two.

I have a little more understanding now of how CSS and HTML work, but I wouldnt know where to start trying to get it working in earlier IEs. Am I better off just making a duplicate site for those browsers or is there a neater way of doing things?