COFA isn't too hard to find. Just make sure you have a map, ask a bus driver, and maybe give yourself a little extra time in case you do get lost (though I'm sure you won't). If all else fails, ask someone on Oxford St.
COFA is on the right side of the road, as you come down from the city. There is a service station just outside (think it's a Mobil) so that should be a good clue. From Oxford St you can see the campus art store too.
It basically goes, Mobil slightly in front of COFA, COFA, Greens Road, Victoria Barracks.
Looking out for Victoria Barracks is your best bet, because there is a break in shops on the right hand side - just trees and sandstone wall. The barracks are huge too - so any bus driver will know definately what you're talking about.