For information on studying in Canada, please refer to the Citizenship and Immigration Canada website at www.cic.gc.ca and look under the menus: Immigration > Study (see also http://www.cic.gc.ca/english/study/index.asp)
For information on Study Permit renewal, please refer to: Extend your study permit
http://www.cic.gc.ca/english/study/study-extend.asp
For Information on Visitor Visa renewal, please refer to: Extend your stay in Canada as a visitor:
http://www.cic.gc.ca/english/visit/extend-stay.asp