What are the procedures for me and my son to get chinese residence or if not a long-term chinese visa?

i am married with a chinese girl for 10years and now we would like to live in China whilst my 9 yr-old son would like to go and study in China. According to China Immigration Laws, a person cannot have dual nationalities, and so the question is whether we need to go all the time to Beijing for our China visa renewal or for Mauritian passport renewal .