VISA question after marriage with a Chinese

I am going to china this spring to marry a Chinese national, I will go there on my present multiple entry visa which is good until August of this year.

After I marry her I plan on staying there indefinitely, can I change my VISA while there to permit a longer stay than 30 days? What kind of it will I need after marriage to stay longer than the 30 day limit on my present one. Can I apply for it in China?