how do i get a new 30days entry and where?

i came to china on a business visit,so i have M,but because due to a delay i had to extend it twice which is the only amount of time a visa can be extended...unfortunatly a school i applied to study chinese said i had limited time on my M for them to process my admission process so i should get at least 30days entry one to be able to proceed with the admission process...i am from ghana and the expensies for me to go back is very high...can i go to hong kong or thailand for a new one?