not really your fault... the game is not well-coded.
still, you'd benefit more from a newer, gaming set up. ( e.g. core i5 2500k + 16 gb ram + cooler master hyper 212 plus + asus z68 motherboard + gtx 560/560ti + 80+ rated 550+ watt psu with good amperage on +12v rail)
have you tried overclocking your cpu? get a good cpu cooler if you do so.
the 2gb vram is wasted on the weaker gt 430 gpu. try to get one like 5770 (depends on your display res., budget, psu) to gtx 560 ti.
what can i say... i love ram.
it was a sample configuration anyway.
okay, change the ram to 2x 4gb ddr3 1600 dual channel kit.
@OP: if you have the game in possession, install it and give it a go. lower all the gfx detail to the lowest point. then slowly turn up draw distance and view distance. disabling shadows could increase fps. keep raising the settings until you reach a balance between playability and gfx settings. you could also try disabling framerate limiter and vsync - the latter might cause screen tearing though.