getting china residence permit from bangkok

At present I am studying in China as a student and my visa type is residence permit for foreigner which will be expired by Sept.20, 2017. Usually the university will be responsible for extending the residence permit when it is nearly expired. However I am planning to go back to Thailand in June and I will be back to China in October.

Now I have a problem because the university refuse to extending the residence permit for me because it is too early.
Can I go back to thailand and extend residence permit at the China Embassy in Bangkok? If I can do so, what are the documents needed for applying the residence permit? Any advices are welcome.

Sincerely yours,
Jessy