Yes you can get Malarone there, but there may be an issue getting Malarone junior if you're travelling with children. Doxyciclone is also readily available and cheaper.
You'll need to get a script though because its not over the counter - Raffles Clinic (Northbridge Road) is a walk-in and can see expats/tourists at about $150USD per visit. Its not cheap, and likely not covered under your travel insurance policy (??). about 7 years ago
Make sure to call ahead to see if they have an in-house pharmacy that will dispense the medication for you. You can also try the Gleneagles Hospital (Napier Rd) or the International Medical Clinic (multiple locations) but be sure to check that they can fill what you expect to be your prescription. Several years ago we had problems getting our prescription for Doxycycline filled after; eventually, we had to go to a hospital pharmacy. For a little additional information on getting malaria medicine overseas you can see the Web page below.
http://www.southeastasiatraveladvice.com/2010/01/get-your-malaria-medicine-overseas-and.html about 7 years ago