I am sure your wife has been doing something while in the States to maintain contact with her heritage. It will be the same thing for you while in TW.
We try to keep in touch with people from our countries and speak our mother tongues on daily basis. Sometimes it may be more difficult, e.g. you can't find anyone who speaks your language. This you should not worry about, there are plenty of Americans in Taipei.
Try to find another American (or American-Taiwanese) family and meet them regularly. For children: cartoons in English, books in English, international school (if possible), playgroups with foreigners. If you have family in the US, let children have a regular contact with them over the Skype (so that they can see each other). I must say that Skype helps a lot in our family. Our almost 2 year old would never remember anyone from our families, if it weren't for Skype.
Maintain your traditions while abroad, whether it is Christmas, Hanukah, etc. always celebrate it. It will be different away from home, but the important thing is: do not forget about these important dates to you. In Taiwan you won't have holiday for Christmas, so it is more difficult. Depending on the job, you can always try to arrange a free day during that time.
We will be also moving in a few years time to my husband's country. Seems that mixed marriages must take into account moving to different places. We believe that this is the only way that children can learn about their heritage. We will see if it works.