Hi Palexon,
Judging by your system spec I can safely say that the processor is definitely up to the job. The RAM has enough memory however I am not certain which frequency/latency it is running, although it should also be good enough. Unfortunately the GPU is a low end ATI offering which is now a few generations old, it is definitely the bottleneck in this scenario.
Before you touch any of the hardware I would recommend that you play around with the graphics setting, gradually reduce them until you hit playable frame rates. If you have a budget I would recommend a GPU upgrade, perhaps a Radeon 6950, they are quite cheap now, don't use too much power and should play this game with ease.
Cheers,
Fultre