Need GPU advice for 2013

Looking to get some ideas about whether or not to upgrade my rig this coming year.

First things first...current specs:

CPU: i5 2500k 3.3GHz RAM: 8GB G.Skill Ripjaws X Series SSD: OCZ Agility 3 128GB Sata 3 MB: AsRock P67 Extreme 4 GPU: 2x MSI R6950 Twin Frozr III PE/OC 2GB

With this current setup, I get fairly good FPS in Skyrim after a lot of tweaking (45-50 FPS outside, settings maxed).

I've found having a Xfire setup to require a bit more tinkering to get dialed in. Still, DayZ, for example, feels a bit stuttery...I've had to turn down shadows and item detail. Now, we're talking micro-stutters, not a slideshow, so I realize I may be seeking unrealistic performance.

I'm curious if I should sell the Twin Frozr cards for a single more powerful card? I'm also concerned about AMD, as I feel like their driver support isn't great.

Games I'm looking to get as close to optimal as possible: DayZ, BF3, Skyrim

Thoughts/suggestions are welcome!

Thanks!