o yah great catch man I forgot to look at that.This won't work, there's only one PCI-E slot on the motherboard that comes with it (ASROCK MOTHERBOARD Z97 ANNIVERSARY)
If you're just planning on replacing the graphics card, there's no point in buying a pre-built computer anyways IMO.
Something like this might work if you're willing to build the computer yourself: http://pcpartpicker.com/p/8CbnMp
You can buy most (if not all) the parts from Newegg.com