it all depends on what the power draw of the other components in your computer draw, in that picture it shows you using an i3, so you figure around 65w for the cpu, the 660 has a max power draw at 140w so maxing out both components at once will lead you to around 205w, that is not counting your hard drive, fans, RAM, motherboard power and other things like usb drives. id say it could run it, but i wouldn't recommend trying it. if you have some spare cash upgrade to something around 500w, you can find them pretty cheep ~$50 for a decent brand.
I have a 300w PSU and using 7750 with no problems. Could be another alternative that's similar in performace to the 650 and I know it works especially since it doesn't even need a 6 pin whereas a 650 does.
202 watts using a psu that's roughly 83% efficient, that's about a 168 watt DC load or about 56% of the power supplies capacity
If you plan on trying to overclock the snot out of it and run Furmark 24/7 to check the stability it's not enough
If you intend to use it for gaming for a few hours a day it's fine
This is exactly what I plan on doing. A buddy of mine wants to play Borderlands 2. He said my Shuttle XPC was godsend for LAN parties. I want a video card that will play all the modern games within reasonable settings without upgrading my PSU.
The same 300W PSU was able to power a GTX 560 (non ti) running the CPU and GPU benchmark -- power consumption was 285-290 watts (in about the 8:15 minute mark in the video).
However, that was running Prime95 and Furmark.
So maybe with normal use and some moderate gaming I'm good to go with the 660.