Rear brakes arn't hard, you just need to tap in the bearing race & fit to the car, no special tools needed, apart from a suitably sized drift. Easiest way is to tap the bearing race out of your old disc, and use that to tap in the new one
Buy yourself a haynes, all those jobs are easy DIY, apart from the tracking of course. Zaust system can be a bit of a nightmare, but with someone to help you should be ok. Get a jack & axle stands or some ramps
Best place for service items I've found is AVS:
http://www.vwspares.co.uk