Change of Employment and Residence Permit

First of all thank you for the very detailed and informative article. I have not found anything else as helpful on the web. I am currently in China teaching English at a University. My whole family is here. We have residence permits that expire in November of 2012. This fall my wife will be going to work for a company in another city. It is nearby, but not the same prefecture. From now on her employer will provide our visa (residence permits). They say we will need to get a temporary residence permit in that city. We are headed back to the states in July and will be returning in September. We are a little bit confused about the process. Should we begin the process now before we leave in six weeks, or will being outside of China be a problem? You mention that if we are changing employers the process doesn't have to be started over from the beginning. How can we find out more information about how to pursue that?