get a new PSU first then get the GTX 560. and don't worry about bottlenecking the card. it will only bottleneck it on some games. trust me, i've been there.
OK AFTER UPGRADING IT, SHOULD I BUY I7 2500 @ 3.30 GHZ SO AS TO PLAY GAMES LIKE BATTLEFIELD 3 AND ASSASSINS CREED BROTHERHOOD ON HD. ALSO, WILL IT STOP MY BOTTLENECKING