If you need a new disk, pads and bearings, you are as well doing it yourself as the wheel will be off anyway.
Remove the wheel, unbolt the disk and with the wheel on a workbench (or kitchen stool) use an old extension bar from a socket set, put it through one bearing until it hits the bearing on the other side of the hub. Then hit the bar with a mallet, moving it round the bearing, and it will pop out. Turn the wheel the other way up and repeat with that bearing. When replacing the new bearing, place it on the housing, and by sitting the OLD bearing on top ot the new one, start tapping it into the housing ensuring you move round the bearing to keep it straight. Repeat on the other side and the jobs a good un*
Fit new disk and pads, replace wheel and you have saved around £100 in labour
* Of course if you have a press or vice, you can press the bearing in.
Grouch, If you must go to the shop ask to sit in and watch the guys at work, it will give you an idea of how to do the jobs in the future