In a word, yes.
You've got an Athlon 64 processor, so it supports SSE2, which seems to be the problem with the current early demo as far as those of us (myself included) with older AMD processors are concerned (hopefully CA will have extended compatability by the time of release).
Another 512MB RAM would probably improve performance (assuming you've got WinXP, that uses about half of the 512 you've got, leaving you effectively with 256 plus the pagefile), but it doesn't look like that'll be essential for playing the game.
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