The reason you can't find the G310 to buy is that Nvidia made it only available to what is known the OEM channel, basically means it can only be bought from system builders (Dell, HP, etc). Spec and build-wise the G210 and G310 are identical, so in what way does it not fit? If it is the back plate bracket that is too long the card should have come with a second shorter one (2 of them actually) like the ones shown here,