I would perhaps check out the Beijing Central Conservatory of Music to see if they offer guqin courses: http://www.ccom.edu.cn/news/

If the Beijing Central Conservatory of Music doesn't offer guqin courses than you can try the alternative which is to place an ad on one of these sites. I have seen people playing the guqin that don't teach at one of these fancy centers, however they could teach you like a private tutor does. It would be cheaper for you as well and you can have more one on one time. Just place an ad that you are searching for a private music instructor to learn how to play guqin. You know musicians don't have a lot of options so I'm sure someone will respond to you with that opportunity you have presented to them.