I haven't had a problem on my headset yet, but I thought it will be lot easier to find the correct part here (US) than in Taiwan. Are you sure the bearing is not worn out? FYI, I checked eBay and there is a replacement for the bearing,
If you decided to get the problem resolved in Taiwan, you might as well bring the headset and the fork back there to see what is the best solution for the problem.
Good luck.
PS: sorry, it will take me forever to type in Chinese.