I have already two Chinese MS students in my laboratory.
You could apply your MS to the administration office in KAIST.
(我觉得这里少了if)Your MS performance is very good, then you could advance Ph.D. program, I think.
If you pass the enterance exam. in KAIST, then everything is supported by the Koreangovernment including your tuition and expenses.
Everything is OK for you except for your GPA, I think.
Therefore, you have to improve your GPA during the final spring smester in 2006.
Anyway, you could apply your MS to KAIST for two ways( times):
one is March or April in 2006 for your starting Fall ( Sept. 1st ) of 2006. otherwise Oct. or November in 2006 for your starting spring ( March 1st ) of 2007.
For the more detail, please see the following KAIST website: