How can i get Rome II to use my Nvidia GEforce Graphics card when it's only using my Intel one?

[Dunadd]

In graphics options i thought it was strange that it would only let me use Low or Medium. Then i noticed it's showing the Graphics card as my Intel HD Graphics 4000 one rather than my Nvidia GEForce GT 640M. How do i get it to use the Nvidia card instead? Can't see any option to change the graphics card in the Rome II Graphics options when i hover the mouse over it or click on it.

EDIT : Just had to go to Control Panel > Hardware and Sound > Nvidia Control Panel and add Rome Total War to the list of programmes and choose the Nvidia graphics card then click apply