I know how you feel. Went to Singapore a few years back (2002 in fact), damn the humidity hits you in the face every time you step outside. Air Conditioning runs 24/7 in that country, every cab there had em on full blast (but public transport is better - TV's in Buses )
I stayed on Orchard Road, more shops than you poke a wallet at. Where abouts are you staying??
Check out Sentosa Island if you havent been already, theres a place called Dolphin Park, you can literally swim with dolphins if you got enough $$$.
In regards to cars, not much to see there. Taxes make up 150% of purchase price for any cars and i didnt see anything special... you were lucky to see a skyline