Either wait till next Tuesday for the Beta if you preordered BF3 on Origin or bought MOH. If not that, wait till next Thursday when the Beta becomes available to everyone.
This game will not be a console port and was built with PC in mind, but since it will be able to run on a console, minimum shouldn't be too hard to hit with 2007-8 hardware, which it sounds like you have. I can't imagine those specs hitting high, though, even at that resolution.
Having said that, I repeat my earlier sentiment, and highly suggest you wait a few more days and see for yourself if what you have will be sufficient before you make a decision.