How many watt PSU would I need for this system?

*Motherboard - ASUS Sabertooth 990FX AM3+
*CPU - AMD Phenom II X6 1090T BE Thuban 3.2GHz
*GPU - EVGA GeForce GTX 560 Ti FPB 1GB (01G-P3-1561-AR) And if you could, tell me how many watts if I were to SLi this card?
*RAM - CORSAIR Vengeance 8GB (2x4GB) DDR3 1600 (CMZ8GX3M2A1600C9B)
*HDD - Western Digital Caviar Black WD1002FAEX 1TB 7200 RPM SATA
*DVD Drive - ASUS DRW-24B1ST/BLK/B/AS Black
*Case - Cooler Master HAF 922 Blue Edition
*Fan Controller (2x200mm & 1x120mm) - Sunbeam PL-RS-3 Rheosmart 3 Fan Controller
*CPU Heatsink - Cooler Master Hyper N 520

And is there anything wrong with this system that I should change?