On a budget build, I'd drop the ssd for a 500gb or 1tb HDD and use the extra money to improve your GPU. Also, 8gb of cas 9 RAM is best. BF3 is intense game and needs resources. I have seen as much as 6gb used while playing bf3.
500w PSU is fine. Buy corsair, sea sonic, or cooler master. Get 80 bronze.
What is your monitor's resolution?