Looks like your "new" PSU doesn't comes with this kind of connector:
On the other hand, could you please tell me which kind of GTX 660 Graphics Card you are currently installed on your Vostro 470?
Since I'm looking for the answer of whether an ASUS GTX-660 card (with length 256mm / 10.1 in) could be installed on a Vostro 470 machine or not, before making my purchase of the said Vostro machine.