If you are gonna get dual video cards, make sure your computer supports it. Open up the case and look at the motherboard, then find your video card slot. Is there another slot like it? (usually black color) Or just find out what model number it is, then search on it online and see how many PCI-E slots there are.
EDIT: I looked up your model and it says your motherboard has only one PCI-E slot, which is now being used up by that 7300 card. There is no chance for dual cards, so your only hope would be that you have enough money for a new video card. If you buy a new card, you might have to change your power supply because it is too low. 305 Watt DC Power Supply. 305 Watts is not enough for a fairly newer card and your other system components. You're not gonna have any power left in that thing.
Memory: 2 GB is good to have and is standard these days. Before you buy, you have to make sure that it matches your existing modules in terms of speed and PC-**00 number. it might be something like PC-4200 or PC-5300, depends on the system. Your memory right now must be at 533 mhz, so make sure to get something that is also 533 mhz. If you get modules at two different speeds, they will both run at the lowest speed available, so it's a waste then if it's not correct.
