I think you can get them they are Campag standard 45 degree bearings and its a Cane Creek headset I think -
http://www.sjscycles.co.uk/cane_creek-cane-creek-headset-bearing-for-is-2i-1-1-8-inch-prod20754/?src=froogle although out of stock there
but for cost of bearings and so you are certain you are not ordering the wrong bits you are probably best off replacing the full unit, I would go for something like an FSA Orbit MX, you can pick them up pretty cheap
http://www.on-one.co.uk/i/q/HSFSOMX/fsa-orbit-mx-headset and then replacement bearings are alot easier to get hold of, thats what I did anyway (the bearings on my original headset where completely shot when I replaced it, and that was one of the shortest lifespans of any headset I have ever had, Im assuming its not very well sealed!)