Pakistani Citizen studying in Korea , Will attend a conference in Chongqing from July 15-18

Hi,
I have the necessary Invitation letter from Conference Chair, I have the hotel and flight reservations, I have 4 Major questions
1. Do I have to apply for visa via an Travel Agent or I can directly apply to CVASC
2. My Alien card is valid uptil 30th September, If I apply for on 9th June 2014, will the validity of ARC be calculated based on application date.. or departure date?
3. My wife who is a Brasilian National living in korea on dependant passport will be going with me in this travel, Should she apply as my dependant (based on my invitation letter) or she should apply seperately as tourist
4. Do I need to show a bank statement? if yes then how much
A bundle of thanks