[citation][nom]Bigmac80[/nom]OMG is it the right time to build my pc on April? What if i build my pc and it doesn't run it good enough ..[/citation]
If you can, hold off until AMD comes out with their new chips and Intel get's there chipset problem sorted.. that way if AMD has something competitive, it may be a better option, or if not it may at least drive the prices of Sandy Bridge chips down a bit. Also, same with video cards. You are going to need a pretty hefty video card for this game so I would wait as long as you can to make sure you get the best bang for your buck on a video card.
And to anyone else thinking about building/upgrading for BF3, definitely go for at least a quad-core processor. Bad Company 2 is one of the few games that really utilizes 4+ cores very well, where most games don't seem to benefit at all from more than 2. DICE is really stepping it up a notch with their Frostbite engines.