Well... We can't really tell yet what card will be the best option for playing BF4.
You can always look on this article:
http://www.tomshardware.com/reviews/gaming-graphics-card-review,3107.html
This should help you deside how much money you are willing to spend and on what.
Hope that pointed you in the right direction 🙂
Please accept solutions if they are correct and press the XP button if somebody helped you. This way you case will show as "Solved" thus helping others with the same problem.
Kind regards, Tviggah