should I upgrade my cpu or gpu?

Yup, those two guys above me are correct indeed, the main issue here is your GPU, your cpu could actually handle the game pretty well IF you have a good graphics card to team it up with, since all games are 75% GPU dependent, then it's absolutely necessary that a gamer must invest a little more in buying a decent GPU.

First, try to download and install coretemp (cpu temp meter) and GPU temp (gpu temp meter) so that you could monitor both :

http://www.alcpu.com/CoreTemp/

http://www.tomsguide.com/us/download/GPU-Meter-Gad...

Next is a faster GPU, the most affordable card that I could suggest to you is this :

SAPPHIRE 100315L Radeon HD 6850 1GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity - $150

link : http://www.newegg.com/Product/Product.aspx?Item=N8...

The HD6850 is a good card that can let you play all games on high settings and some on max settings, it is currently ranked #15 in benchmark and is a step higher than the gtx 560 (ranked #16) BUT much cheaper (the gtx 560 is $200 at newegg). Its power requirement is 500w or greater so a 600w +80 corsair builder ($70 at newegg) is good enough.

But it would be much better if you could afford the RADEON HD 6950 or GTX 560 ti (they are both $240 at newegg and has almost the same benchmark scores, ranked #8 (Average G3D Mark = 3050) and #9 (Average G3D Mark = 2971) respectively.

>Eah 4850 1gb ddr3

This is your issue here. Ideally you will want to spend about $200 dollars on a graphics card to make it a "significant" upgrade. You can go for less, e.g Radeon 6850 but it will not be a big improvement. Try a GTX 560 Ti.

6850 - $150

http://www.newegg.com/Product/Product.aspx?Item=N8...

GTX 560 Ti $210

http://www.newegg.com/Product/Product.aspx?Item=N8...

>cpu: Amd phenom II x2 3.5 ghz (3.1 ghz)

I would try to unlock this processor. If you're lucky, you can unlock the extra 2 cores and turn it into a quad core Phenom. If you're not, you can just overclock it (needs good air cooling) and aim for a 4ghz speed.

>I also have problems such as weapons not showing.

Is your hardware overheating and is your graphics card driver on the latest version?

i might recommend which you improve your CPU 1st, the whether the GPU has pass processors to render the image on reveal, the documents for those pass processors would desire to be processed mostly. As you would be able to desire to renowned, the CPU is between the main crucial aspects interior a working laptop or computing device equipment, upgrading will velocity up technique time. If gaming is your hobby, then palms down improve your GPU first.

Upgrade your gpu, but the fact that guns are not showing sounds like an overheat, download a free hardware temperature monitor and see what parts could be overheating, if something is overheating check all fans for blockage and add a couple of additional fans.

upgrade your GPU..Bf3 is abit buggy at times.i'm sure people are experiencing what you are