Need help upgrading my system

Hello, I am a Battlefield 3 player and I basically built my computer for Battlefield... I'm not feeling satisfied with the FPS, as I'm getting some lag even running on High, so I would like to upgrade my computer to get possibly Ultra graphic settings... I don't want to go OVERBOARD and spend a crazy amount for this, but I want it working BF3 on Ultra and have no issue running BF4 when it is released...

So here are my specs below, please tell me what I need to upgrade to fix my graphic setting issues.

Also, could you pleasew explain what the process would be? I have never upgraded before, but I did manage to put the thing together, lol.. Would I lose my OS and programs if switching out a processor or motherboard?

It would be greatly appreciated.

Budget? I think 7870 would be solid.

$300 Max. I looked this up: http://www.newegg.ca/Product/Product.aspx?Item=N82E16814161404

You're saying that would do me good? Should I also upgrade my motherboard? Or is that unnecessary? And how do you switch out a processor? Do you lose any files or anything?

This should max it out for bf3, checkout the youtube channels. The game itself does get very demanding in 64 player situation, so is natural to take a few clicks down. Personally I turn everything down on MP so the game runs much smoother. Upgrading a gpu is very straightforward, unplug card and take it out, plug new card in place, and install new drivers.

You may or may not need an upgrade for bf4, I don't know since the game is not out yet obviously. If you upgrade you most likely need a new socket in other words motherboard which is best to reformat.

K sorry boys, I meant to ask if I only need to change out the video card? Or should I change my processor? Because my CPU Usage hits 100% whilst playing BF3 on high.

What if I replaced my 6850 for a 7850/70? Would it be compatible with my motherboard? Or would I need to replace?Devoo55

No, it'll work. Upgrading the gpu will be the biggest difference. Sell your old card to boost $$ if necessary.

Overclock your CPU and get a 7870 xt or something.

Yep it will be compatible, no problems there.

http://www.newegg.ca/Product/Product.aspx?Item=N82E16814161404

This one is also good for an extra $20 after rebate, you'll get a bit more performance.

Your CPU would be fine with a bit of an overclock.

K sorry boys, I meant to ask if I only need to change out the video card? Or should I change my processor? Because my CPU Usage hits 100% whilst playing BF3 on high.

Devoo55