yes that's right the rears are adjustable. If anyone tells you otherwis. people down the pub or garages alike, leave well alone.
You need a place with a good 4-wheel laser alignment machine, the rears have to be set first then the fronts. watch if you can to make sure this is done. A good place will take you out and show you the angles before and after on the computer and at the least provide a print out.
It's not a hard job at all should be round about an hour done properly but the track rods are prone to seizing up which can be problematic.
anywhere around £40-60 seems to be the norm but there was a thread on here a few weeks back where someone was quoted over £200!