I suggest you go to Jeff's Japanese training in Wuyi Square, which seems to specialize in Japanese training. I read on their website that there seems to be an intermediate Japanese training class recently, as well as a direct class from N4 to N2. Some of my friends are studying there. It is said that it was opened by a teacher who has studied and worked in Japan for 15 years. You can search "Jeff Japanese Training" in Baidu to find their website, hehe.