Does my psu support this config?

Hi

assuming your PSU has a PCI-e 6 pin plug for the graphics card it should work

http://www.geforce.co.uk/hardware/desktop-gpus/geforce-gtx-550ti/specifications

If you are buying new parts I would get a new better quality pSU
I am not sure how that PSU gets to 500W from its individual voltage & current indications

if using existing second hand parts I would probably go ahead and take the risk

regards
Mike Barnes