Where to submit application for Chinese Visa in Kolkata?

I want to visit Beijing, China for a conference purpose on 01-02 Sept. 2013.
(1) Where I have to submit the application in Kolkata, whether in the Chinese consulate itself (i.e. EC-72, Sector I, Salt Lake City, Kolkata-700064) or in the CVASC i.e. BIPL Building Omega, Ground Floor, Bengal Intelligent Park,Block EP&GP,Sector V, Bidhan Nagar, Kolkata, 700091)? Last year I visited Shanghai for the same purpose, but I submitted application in the Chinese consulate itself.
(2) After how many days I will get it?
Pl. reply.
Prof. R.R. Pal