Computer question(I know its annoying)

Yeah I know its annoying, people asking for help. We're noobs, just bear with us.

AHEM.

I recently bought this computer during the middle of summer. In the pamphlet, it said that it was dual core. And now I just started to wonder, this is odd, how come it only says I have 1GB RAM?
In my DirectX Diagnostics, is it supposed to say that I have Dual Core?

One more thing, you think this is good? http://cgi.ebay.com/SAPPHIRE-RADEON-...em230040184356
at that price?
http://cgi.ebay.com/SAPPHIRE-RADEON-...em230040185660

Thanks for your time.

It has a dual core processor. RAM isn't associated with processing power. As for the video card, I have no clue, sorry. -.-

Choose whatever floats ya boat.