Last time I travelled to Singapore, I got a visa from San Francisco itself, but that was only because I was going to stay there for 4 days or so, on my trip back from India.
But if your trip is 2 weeks away, I wouldn't advise you to go through the visa process. Usually they take about 5-6 days, but that is only if you have all your documents in order and usually you will end up not providing exactly what they want like letters of recommendations etc.
A lot of people just take the transit visa on the spot, and it is usually granted. Keep in mind two things, one there is a huge line for the transit visa, so the moment your flight lands, make haste and get in line. And two, pack your bags accordingly, Changi airport has a baggage check for some nominal amount, so you can leave your bags there while you travel around Singapore.
There is a metro rail right from the airport itself, so it is very easy to travel. I definitely recommend a visit to Newton Circle, if you are in anyway into sea food. And offcourse a trip down Orchid road. The food is simply awesome.
If you don't get a transit visa, there are enough things to do in the airport itself, they have internet connection, TV's, game etc. Should be fun. So nothing lost.
Enjoy your trip, just be careful of SARS!
