Go to pcpartpicker.com and enter your system. It will show you the power required and indicate if there are any problems with the build. But generally speaking, 650W is plenty for any single graphics card system.
Well since you've been using it for 3 years the psu must have degraded a little. But you should be fine since the gtx 670 draws a little less power than the gtx 260.
If you want to be safe get a 500w or 600 w psu with a good brand (your current psu looks like a no name brand)
I find OCZ is cost effective brand, but not top of the line. Antec is good too, but depends on which line of psu's. Corsair is really good (although a little overpriced imo), besides their builder series which is decent but not great. Theres so many to choose from its hard to recommend one.
Heres one on sale 620w antec for $50 after rebate. Will be more than enough for your current build. It leaves a lot of headroom in case you upgrade again.