VAG.com is good, but u can get a reader for cheaper, that will erase the fault codes for you and read them. VAG.com can do all sorts of fancy stuff, but also if used wrong can cause big problems. As you can edit things.
I have this:
http://www.talktomycar.co.uk/products/codereaders/mj001.htmAnd reads codes for engine, abs, etc etc. And can clear the codes.
Best advice would be to fix the light. Erase all the codes (as old ones will still be on there that may be fixed)
Drive the car for a few days 100miles or so. Then read the faults and you will know what is and isnt broken.
Also abs faults can be intermitant. Once my abs light would stay off but when it rained it would come on, as the sensor was shagged and water got in, but when it dried out it was ok, lol.
Thats the best advise i can give you from my personal experience of owning a mk3 for too long. haha