The website seems to be recreational (nothing towards coorp users) which would be at MIN running Windows 2000 (Windows 2000 can run up to IE6 only). XP (your true MIN "core audicence") runs up to IE8. You should test against IE8 if anything.
Even if that, if this is a new website, its for your future audicence: Most of your future audicence will be running at least IE9.
Web developers have to STOP testing against old versions of Internet Explorer. This is 2013 people. If it doesnt work, the public should upgrade to a newer version of their browser, not the other way around. IE6 is older than XP. IE8 can run on ALL OSs (except Windows 2000) than run IE6.
If you really want to help your users, detect if they are running IE6 and Windows 2000 (or below), and resend them to a page that explains in a easy format that they should use another browser such as Firefox or Chrome. If they are using IE6 and something newer than Windows 2000, directly redirect them to the internet explorer homepage.
DO NOT HOLD WEB DEVELOPMENT BACK AND MAKE IT EASIER FOR THE REST OF US DEVS.