Don't pay someone to fit this when you could do it yourself, the pump is only bolted to the engine via a few brackets which don't actually need to come off. You will need to drain the PAS liquid off, just unbolt the pipework from the pump and have a bucket ready.
As for prices, you could pick up one 2nd hand, i picked up a whole PAS kit up for ?75 with a view to fitting to my car.