You'll know it's the regulator when the window falls to the bottom of the door.
My VW dealer had the parts in stock (surprise surprise) for $125. This included the new metal runners and a new cable spool. Whilst I'm dirty at having to do the job at all, I found the parts surprisingly cheap.
The job itself takes a couple of hours, and I followed the instructions at http://vwgolfr32.co.uk/windowregulator/
If you are doing it, BE SURE TO GET THE PARTS FIRST! I made the mistake of taking the door apart, then going to get the parts. The door wouldn't open again! I don't know what i did to get it open eventually, but I did.