Q: if i add 16 gb to my mbp late 11 then how much graphics i get

No. The RAM is not for any Graphics. It is for the main system.

Read here about the maximum video memory for your intergrated graphics vs the amount of RAM installed:

http://support.apple.com/kb/HT3246

if you own a 13 Inch Macbook Pro - upgrading to 8GB or 16GB increases your VRAM in your built in Intel Video 3000 graphics to 512MB from 384MB.

on a 15 inch Macbook Pro - it's a non-issue since your Macbook comes with it's own discrete graphics adapter.

see image below - late 2011 13 Inch Macbook Pro - with 16GB of RAM.