I would suggest you pop into Hong Kong to solve your 64-bit vista problem. I was able to pick up an English copy of Vista will there.
As for upgrading, I would suggest getting more ram first. Mainly it will allow you much better overhead when you have multiple copies running. After that I would suggest you upgrading into a GTX260 instead of a 280. Aim for the XFX GTX260 Black Edition, it has the same scores as a stock 280. It runs for ~$280 on newegg. I'm not sure how much it will run you in Guangzhou, I know for Shanghai there'd be about a ~200 RMB premium on a XFX. Hope that helps. Also thinking about Guangzhou has given me a mad craving for some Cantonese food.