well, this question will never have just one answer, it depends on you, your motivation, what you wanna improve (seems to be read and write here), if you're willing to pay for it ect...
just a small add from a friend but you could go check out www.chinesetutor.net and ask Simon Laing to explain you a bit more. Say it comes from Lucille the Frenchy who was in Leeds.
Then, more seriously, play wow in Chinese, not English. It's gonna be hard at first but then, you'll be like swimming in a pool.
and in general, read comics and kids books in Chinese, you can even find comics translated like Garfield if you feel like it.
Then, do like the Korean must do all the time, talk to an Chinese friend all the time, chat on msn, watch DVDs subtitled, write pages of characters everyday...
Many friends also say the best way is to date a Chinese (but that would be more for your oral), but don't do that just to improve ur skills.
you also have www.chinesepod.com which is great for the oral (all levels included) and is free.
watch Chinese youtube on www.tudou.com, www.youku.com ...
Then, in Chongqing you have the univ of foreign languages or something like that. Every.... Thursday or Wednesday the students go to the Moon or the Sun place and chat according to the Language chosen (I think it was French on Thursday and English en Wednesday). Great way to socialise with Chinese students.
Or just buy a book to learn Chinese. The Beijing Univ Editions are quite alright, altough I'd recommend any with clear exercises in ENglish, Grammar and CDs / tapes to listen. (sorry don't have any precise name in mind, and I think Youfeng publishers would be the best but they're French).
But if you do it the CHinese way (memorising by heart without really thinking about it or using it in exercises ect...), you'll get bored and won't remember a thing.
Try to find fun ways to learn it like i suggested above, and don't compare yourself to the Koreans, I had the same problem and the teachers were just following their level, not the western students level which was shit. +, the Koreans in my class all cheated for their exams...
i don't know if that was very clear, but don't hesitate to ask me to clarify a bit more.