Should I first upgrade my 5750 or my x4 955 BE?

Heres the thing. I am deciding between spending a few hundred on either a new cpu or a new gpu.
My PC is mainly used for playing BF3 on a 1080p monitor. Right now, graphics are okay, but I want better.
Is my CPU or GPU in more need of upgrading?

I want to get the 8 core amd cpu but i also wanna buy a 6950. which should I do first?

Heres what I got going for me right now:

Phenom II X4 955 @ 3.8 GHz
GA-970-UD3 motherboard
16gb Ripjaws 1600 MHz
Radeon HD 5750 1GB GDDR5
128GB SSD Sata 6gbps
700W PSU

So should I get me the new 3.1ghz 8 core bulldozer and stay with my 5750, or stick with my X4 955 and grab a 6950 2gb GPU?
All other suggestions are welcome. I feel like I know what Im doing, but not compared to you guys.

I would rather go for the upgraded graphics card myself, it seems like the better choice. BF3 is more of a graphics-intense game, and the 955 will hold up fine to that work.

I would get the 6950 1GB actually though, saves a few bucks. The 6950 runs out of juice before it can use the full 2GB. Tom's did an article on it.

Overall, you will see more of a difference between a 5750 and 6950 than a 955 and a FX.

The 955 OCd won't bottleneck any high end SINGLE gpu, so you are in the clear.

I really suggest waiting a tiny bit for the rest of the 7xxx series to be released, the 7970 came out today, so there wont be too long of a wait for the others.

1) Your X4 is a good value gaming cpu. The X6 and x8 amd chips turn out to be poor gaming chips. Your X4 is as good , if not even better for gaming.

2) I agree with the graphics card upgrade. Your psu can power any single card made today.

3) To prove this to yourself,
Run your games, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.

If you eventually need to upgrade your x4, look to sandy bridge or, in april, ivy bridge.

The 955 should be just fine for gaming. As for your card, first question is what is your budget?