If you're having trouble finding books about Singapore in bookstores where you live, I suggest you wait until you arrive, then browse local shelves, where you'll find tons of books about the country, its history, culture, arts, food, and local fiction. For interesting and informative reads that you can find (or order) through your neighborhood bookstore, here's a good place to start:
From Third World to First: The Singapore Story: 1965-2000 by Lee Kuan Yew (HarperCollins) details the history and policies behind Singapore's remarkable economic success written by the man who was at the helm.
The Singapore Story: Memoirs of Lee Kuan Yew by Lee Kuan Yew (Prentice Hall). An intimate account of Minister Mentor Lee's personal journey, this book will give insight into one of the world's most talked-about leaders.
Crossroads: A Popular History of Malaysia & Singapore by Jim Baker (Times Books International). A readable history of Singapore and Malaysia from a longtime resident and expert.
The Singapore Grip by J. G Farrell (Knopf). A highly enjoyable work of historical fiction written by a Booker Prize winner takes you back to Singapore on the brink of World War II to examine the last days of the British Empire.
West from Singapore by Louis L'Amour (Bantam). Few knew that Mr. L'Amour was a Merchant Marine in Southeast Asia. In this novel he creates his brand of fascinating American West storytelling, only this tale takes place in the waters around pre-World War II Singapore.