Updates in PC

Hi its me again, Decided it was time to upgrade my upgrades.

So here is my specs,

i5 3570k OC'ed to 4.6Ghz runs at a cold 40-50ish degrees (i have Antec's Kuhler H20 920 turned to full blast and what i think is a 230mm intake fan pushing in some air with 4 Cooler master Sickle flows on the side also pushing in air)
Asus P8Z77 - V board
700w Coolermaster Silent M2 ( I think) its modular
16 GB Ram (needed for intensive Virtual Machine, I like having 2GB each)
EVGA Geforce 560 TI
OCZ Vertex 4 128GB (works flawlessly)
3x 1 TB Western Digital Hard Drives (one is a Seagate, another is a caviar green the other is a Caviar Blue)
5x Cooler Master Sickle Flow Fans
1x NZXT Sentry 2 Fan Controller, Im having buyers remorse on it  

So my question is, Do I have to pick up a different Power supply to be able to SLI in the near future, and What Graphics Card should I use?