Try this school: www.juzmusic.com
Its opened by my friend's collegemate.
They are very new, but the site looks good.
Give them a try.
They are in the Marine Parade area.
I have tried the home kit before. Its quite good, my teeth lightens a few shades. Basically its a tray, you filled up with the given toothpaste like stuff, and put it on your teeth daily for 2 weeks.