Queen Street station, which is located next door. Queen Street serves trains to the north of Glasgow, but trains to the south of Glasgow go to Central station, so if you end up there you'll have to...
Central Station's the main concourse is located on rue de la Gauchetière West and occupies almost the entire block bounded by de la Gauchetière, University Street, Belmont Street and Mansfield...
Well depends what time you go, it can usually be from £44 and above depending on what time you go. There's a direct service on the Midlands train, check the website out...