Need to apply a China Visa for staying 5 days in Guangzhou?

If holding a Singapore Passport, do I need to apply a China Visa for the journey as follows:
21 Jan 2012: Singapore --> China (Guangzhou)
24 Jan 2012: Guangzhou --> Hong Kong (less than 5 days in Guangzhou)
04 Feb 2010: Hong Kong --> Singapore
If I need to apply the Visa, can I authorize my wife to the Embassy to apply on behalf of me, does she need to get an authorized letter from me ?
Do I need to submit any Form (V2011A or V2011B) ?
How many days to get the Visa ?