In response to Release Letters/Recommendation Letters (englishgibson)

However, my "Performance Assessment" is, according to my employer "POOR".

It seems your former employer is a ratbag, but don't lose sleep over his/her 'assessment'.
After you change to an L, you will still be able to get teaching jobs in China. Of course, don't let your new employer see said 'assessment'. So long as you're white, neither too young nor too old, and a native speaker of English with a university degree, you can get a job in China easily, especially if you have a Chinese wife - that's a big plus. You needn't any teaching references. My advice would be to stick to the public sector. Avoid training centers and private schools. Good luck to you, wherever you decide to go next.