Just follow the signs to get a maxi cab. These are mercedes vito vans that can carry up to 7 pax. S$50 fixed price to any destination in Singapore (about $33). No need to bother booking in advance, there are always plenty waiting (and as PP states, 2 regular cabs would work fine too).

Added advantage that it bypasses the regular taxi queue that can occasionaly be lengthly depending on your arrival time