i have gain admission to study and the jw202. i am to register at the school not later than 20th september, 2011 but as at now i have process my visa what should i do.

Why don't apply for China student visa earlier? When did you submit the application?

i have not submitted it because my uncle sponsoring me was out of the country so i couldnot get him to sign my sponsorship letter so i want to submit it on wednesday 21st september, 2011. will my application b accepted. because deadline for registration at the school is 15th october 2011

I'm afraid no. Even if they accept the documents, they may not give you the visa since the requirements are not enough. But you may give it a try.
BTW, it usually takes four working days to process a visa. But one working day and 2-3 working day service is available in Ghana. You may use them if you are in a hurry after you get all the requirements well prepared.