the 67xx series outperforms it. You can get a 6850 (oc edition) oc it pretty high and have almost equal performance of a 560ti for $30-$40 more than what you paid for the 550ti.
Yes it will run the game (at whatever settings, can disable 1 or 2 things to make it run better) but other than that your best bet would be to order a more powerful card when you aquire the cash, sell your 550ti and put that + whatever you have saved up towards something better.
I bought two 6950 2GB to run BF3 (one is currently under RMA now) when it messed up I decided to drop my power usage by 50%~, reduce noise polution by 25%~, Equal temps, performs on par with dual 69xx cards ez.
Yes I wasted $600 on two gpus. but that was my first gpu purchase (thought I would need it to run BF3) *much like how you think you need 550ti to run BF3* and then comes along a card that offers the things I listed in the above line for $200 less than what I paid for my two cards.
SLI/CF you are tempting but a single more powerful card always prevails
550ti is not the most powerful card for its price/performance, therefore I recommend buying something else.
This forums is all over Nvidia's testies so you will always see it recommended on here before any AMD cards.
My regular forums is all over PRICE/Performance ratio and want the best bang for buck. With 550ti never being a card that is mentioned.
Let me know what is the most you would spend on a gpu within the next few weeks and then once you find the card you want you can begin upgrading the rest of your components afterwards once you collect more cash.
The 550ti in my opinion was not made for hardcore gaming like BF3 64player maps. 2GB vram is what you want for 1080p resolution gaming. So take my word to heart and try to find yourself a better gpu.
I.E. you could have spent $25 more and got this card
I got a buddy that runs BF3 on an AMD Athlon II 250 Regor X2 or something with a 550Ti @ 1280x1024 on Medium settings at 60fps (he claims) with no AA and no AF or very little. Depends on resolution you want to play at. @ 1080P you are going to want at least a 560Ti. Before you buy the game see if you got any friends that own it on PC. Ask them to let you login with their account download the game and see how it runs, I did this with my friend because he wanted to see how it would run on his rig, I just spent the day at his house as it downloaded to watch to make sure he didn't mess things up on my acc.