The graphics card says that the minimum power supply needed is 500w. I have a 500w power supply but will this run the graphics card fine without any problems, because if it did cause problems i'd just rather get a cheaper one.
the cables on that unit are nice looking for a 6770, you are fine...but just remember that running an OC with high inside case temps will set your PSU to reduce its output cos of cap stress
so in summation, that PSU will hold with the parts you have in mind of upgrading but will fail if you go any higher...at least thas what I'm reading in reviews and i can't find that PSU on jonnyguru.com
FYI - that 6770 is nothing but a 5770 with the 5 replaced by the 6 and given a slight OC than the 5770(but is the same engine under that cooler)