That has a legacy bios. You cannot run 900 or 1000 series Nvidia cards on that board. Any card from the 700 series, like the 750 TI, or R9 AMD series, will be the best cards you can run on that board.
Yes, you can run 8GB of DDR3 on that board with G41 chipset, but it will likely need to be low density memory. This is available, used, through places like Ebay or some of the memory manufacturers who have old stock, but you will not have an easy time finding it because low density memory has not been manufactured for many years and unlike some boards, that will not support newer high density modules.
http://forum.corsair.com/v3/showthread.php?t=102707