Hi,

You can get 'Super-Brilliance' Xenon bulbs from Halfords. They are £27 each, but its buy one get one free on these.

I have these fitted to my Mk1 focus, dipped, main beam & fog light bulbs & they are really bright & make a difference.
Certainly a lot brighter than the standard bulbs.

I think you can also get HID conversion kits for £50 - £70, if you dont have the Xenons as standard...