Unfortunately, you either take a train or you can:
try taking 980 to the area around National Library, and the
walking over to catch 33 or 145,
try taking 167 to the Stamford Road/Dhoby Ghaut area, and then
catching 64,
or as mentioned, take 167 to Thomson Road, then switch to
132,
but this will either make your ass burn up on a bus seat, or you
will die of impatience simply by just waiting for some of these bus
routes
.