Geforce 550 ti

The rest of PC will hold back the card massively and your power supply may not handle running it at all. You will not be able to play BF3 on high with that system at all, you should be able to play all games on lower settings and get playable frame rates with a few exceptions like large multiplayer maps on BF3 will not be playable on any settings with that CPU. I would advise you save for a new system or get a low end card just enough to play games on low-medium settings (like the DDR3 Radeon 6670) to get by until you can get a new system.

I figured i was bottlenecking it bad but it sounds real bad.
Also i was thinking about adding 2 gigs of ram and upping the PSU would that even help?

It would certainly help (the PSU is essential) but the issues will still be the same though slightly lessened. Unless its totally out of the question in the near future I still think waiting until you have $500 and getting a new build is a better option.

So what could i upgrade to make this rig better?

Buy a new rig? Pretty much comes to a complete rebuild if you want a significant FPS increase. Something along the lines of i3 2100 $100 +mobo $50 4gb ram $40 + $35 psu 450w+(quality brand). ~$250

Not likely, if you did get it all to work, you would not be getting the most out of the card. Its a very weak PSU even for the 550.

Does it have a 6pin PCi-e connector?

I know it wasn't your question but like a few others I would recommend a new build and considering you want to play BF3 would recommend a 560ti, you'll get alot more for your money, as for CPU you'll want the i3 2100 as Supermuncher85 said or maybe a phenom 2 965 if your funds are low

I would get a gtx 460 instead, it is priced a bit lower and it would perform better

I have to say don't get the 550 Ti's they are over priced and they are the worst gaming cards the nVidia has put out. I know I have to of them. If I knew now back when I got them.

I would have never had bought them. For the same price get the 460 or if you can afford it get the 560 non Ti anything but the 550 Ti. Good luck to you and I hope you get the card you want.

So would i 460 work on my rig? and actually give me good performance on a game like mountain blade warband? Because right now i can barely play single player on the lowest settings.

Unfortunately no, not if you want the full benefit out of it and even that will more than likely require a PSU upgrade. You might get away with a 6670, but cant even "officially" recommend that as it is said to require a 400w PSU. You really are looking at pretty much a new build if you don't want your gaming experience to be irritating.

What resolution are you playing at?

my monitor res is at 1240 x 1024

The 460 will also bottleneck your CPU and even the 550 might as well. The only card that will not bottleneck you is the HD 6770 or the HD 7770 unless your tower is a mini tower which will mean.

You will have to get a lowprofile card and the best card to get them in is a HD 6670. You will not be able to get a good fps with any of todays games. You need more ram. You will need a better PSU.

The duel core CPU's are not that good anymore except the new one's like the i3 and some AMD ones. I hate to say it unless you can update your CPU and that would mean will your MOBO let you?

With either card you will not be able to play BF3 due to your lack of ram and your CPU Here are the specs for BF3. If you make min requirements then you are talking about the lowest setting on the game. Sorry for the bad news and good luck to you

Minimum requirements for Battlefield 3
•OS: Windows Vista or Windows 7
•Processor: Core 2 Duo 2.4 GHz or Althon X2 2.7 GHz
•RAM: 2GB
•Graphic card: DirectX 10 or 11 compatible Nvidia or AMD ATI card, ATI Radeon 3870 or higher, Nvidia GeForce 8800 GT or higher.
•Graphics card memory: 512 MB
•Sound card: DirectX compatibl sound card
•Hard drive: 15 GB for disc version or 10 GB for digital version

Recommended system requirements for Battlefield 3
•OS: Windows 7 64-bit
•Processor: Quad-core Intel or AMD CPU
•RAM: 4GB
•Graphics card: DirectX 11 Nvidia or AMD ATI card, Nvidia GeForce GTX 560 or ATI Radeon 6950.
•Graphics card memory: 1 GB
•Sound card: DirectX compatibl sound card
•Hard drive: 15 GB for disc version or 10 GB for digital version

The power supply is not enough for that card, and either way the card is going to be severely bottlenecked by the CPU and your RAM. Right now, you have probably about 2 choices.

The most I would say you could use on that computer is an 8800GT, which is even a stretch. And the 8800GT would require a PSU upgrade. I have an Athlon 4600+ right now and had it paired with a GTS250 and in some situations it was a bottleneck. Now it is paired with an 8600GT.

You could also get a whole new computer. Getting the GTX460 would be overkill as well.

You could get a low powered card, like the Radeon 6670, which would actually go nice with the system you have now.