Protocol
When you get to the top of the slip road at the N4, turn left (not right, as suggested by Ms X).
Go straight through 3 sets of traffic lights. After the 3rd set, the train station is the fourth turn on your left.
You might get a parking spot at the station. If not, go into the Glenroyal Shopping Centre (appox 200 yards past station on right hand side).
There is a free Council Car Park to the LEFT as you enter the complex and you should get parking there at that time. Allow 5/10 minutes to walk back to the station.