Love singapore, everyone is so short, so easy to spot your family when you get lost in the sea of asians in the markets.
On a serious note, the markets are open really late, and food is quite cheap, but servings are quite small.
the offices are usually open the few days before semester starts. You could try then, or maybe ring them.
I would recommend ringing them so you can get it sorted out asap, otherwise your timetable will be very inflexible due to tuts filling up.