GTX 560 Ti. thats the only card that will run fine on your PSU out of those three. and yes you can use your 1 6-pin and a molex to 6-pin adapter on the other. most GPU's comes with a molex to 6-pin adapter these days.
I think I'm gonna get the GTX 560 Ti 448 Cores (Since the eXtreme Power Supply Calculator says I use 407W with a GTX 570)