Judging from those two screenshots, am I correct in assuming that your computer is very new, and very high end as well? I say that because both DDR2 (your RAM) and PCI-Express (your graphic interface) are very new technologies.
The RAM that you gave a link to would not work in your system. The RAM in the link is DDR RAM, and has 184 pins on the actual module itself. The kind of RAM that your computer uses is called DDR2, and it has 240 pins on the module. The RAM in the link would not fit in the slots in the motherboard.
I think this RAM would be a good choice:
Let me know what you think, and I'm curious to hear other people's opinions as well.