While the Litepower 700W isn't a great PSU, only producing a Max of 504W and not even 80+ certified... it should be ok to power your system.
The Asus GTX 560 stock, only consumes about 50W Idle, and 165W on full load... so there is ample headroom for the rest of your components. You didn't post all of your specs so we cant be 100% sure, but I am very confident that the rest of your computer won't consume 340W.