Google Navigation Map is available in US for a period of time already. Now, they are extending this free features to 11 more countries. Unfortunately, Singapore is not in these 11 countries.
An excerpt from Google Mobile blog.
Today we’re launching Google Maps Navigation version 4.2 in Austria, Belgium, Canada, Denmark, France, Germany, Italy, the Netherlands, Portugal, Spain, and Switzerland for Android devices 1.6 and higher. Google Maps Navigation is an Internet-connected GPS navigation or ‘satnav’ system that provides turn-by-turn voice guidance as a free feature of Google Maps.
So, be sure to download the latest Android Google Maps app to get the latest features.