Hi foldinglemon,
Well, it's better than what you have now I suppose, but it's still not really enough I am afraid.
The minimum ATI card suitable for the game, is a 9600 Pro. And that's bare minimum. That might still make the game choppy and slow. The 9550 will most likely run it, and perhaps better, but don't expect miracles or great performance. My experience was that the lower end ATI cards do not perform as well as their Nvidia equivalents, with Shipsim..
Regards,
Fred