I have a xfx r7-240a-cnf4 graphics card. I can't enable eyefinity because my third port is vga. I have 2 displays hooked up/ One is HDMI and the other is DVI. If I purchase this http://www.ebay.com/itm/USB-3-0-to-VGA-Video-Graphic-Card-Display-External-Cable-Adapter-for-Win-7-8-/181511112290?pt=LH_DefaultDomain_0&hash=item2a42e7c662 can I hook up and enable a third display. How can I have three displays with my graphics card?