Kimmy: Depending on your budget, u can get from Egg Maternity, think they have outlet in vivo. On the costly side. Else there's always Spring Maternity, outlets all over, mothercare, kiddy palace. There's quite a few shops of other brands in United Square too.
Personally I have gotten mostly from Spring, Mothercare (undies), Marks n Spencer (undies), and several shops in United Square.
I went for jeans, basic colour pants (black, Khaki, grey), some dressy tops for both work and play, some spaghetti tops for daily home wear/yoga classes, 2 sleeveless shirts for work/formal meetings, 2 t-shirts for dress down fridays, 2 dressy dresses for functions/work, 2 semi formal dresses which can wear to work or shopping.
I could still fit my normal blazer minus the buttons.
I started feeling very warm all the time towards the end, so the sleeveless, tubes, halters work very well for me. But do note that I had quite a bit of darkening of arm pits as the pregnancy went along. So the sleeveless was not such a good idea. I just refrain from raising my arms too much. =P
I also try to stick to knee length dresses so that I don't trip over the lengthy dresses.
Mummies who are intending to stick to normal clothes, do try to get those that's longer in length. Else tummy will start peeping out at the end. Not that nice for work if your work place is quite formal.