SINGAPORE EXPATS FORUM
Singapore Expat Forum and Message Board for Expats in Singapore & Expatriates Relocating to Singapore

You should check out Wilby Residences- the central location--- www.wilby.com.sg/ It's about a 5 minute walk from the Bugis MRT. They have smaller rooms from 3400 a month. Might not be as close to NUS as you were hoping, but definitely much cheaper than many of the other serviced apartments.

I also just arrived in Singapore and am looking to meet some people. Hopefully will see you all tonight.