I hate to say this but have you read what it says.
The minimum requirement for windows is a Intel HD graphics, or Ati card, or Nvidia card equipped with at least 256Mb of memory.
All it is saying is your card meets the minimum requirement.
It is not referring to the total amount of memory the graphics card has.
Just that it passes it`s requirement for windows.
Download cpu z install it, and you will get all the true values. system memory, graphics card and on board memory of 2gb.