I have a dell studio, with a 1400x900 res.
It has a 2.1 core 2, 3 gigs of DDR2 ram, and a ati 3650.
I can run empire at lowest settings with only minor hiccups during the campaign mode, and usually without problems on mid to small battles. I figure with what you have you should be able to run it on low, but at this point it is probably dependent on your tolerance to lag. If you are only doing campaign, and you tend to auto resolve battles as you play on, you should be fine. I beat the epic campaign with my computer, but a word to the wise: large battles will really slow you down, and I would probably say that you should never attempt a ship battle with 2 full fleets or more (being the sum of both sides of the battle) with 3rd rate or higher ships of the line, you'll most likely crash to desktop as your fleets become close to each other.
In short, if you want to play the campaign, you can manage, but if you want to play multiplayer, it will probably be rough seas.
EDIT: the gt220 should better than the hd3650