regarding wheels, i've had wheels from
http://www.wheel-base.co.uk/ before and they offer 6 months interest free, just make sure you pay before the 6 months though.
like Rhyso says the key comes apart in the middle, i normally use a flat screwdriver as it can be tight, use as wide a one as you can otherwise you can mark the key. the groove is under the key blade. once you've got it aprat the bit you press lifts off to show the battery.
what TDI have you got and what size rims you looking at getting?