Irish dry stouts are generally served on a blend of nitrogen and CO2 through a special faucet that helps to produce that creamy, long lasting head. It lasts so long (as I understand it) is because the gas in the bubbles in closer to the composition of air. Without this you won't have the same head or mouthfeel. You can mimic the effect somewhat by aiming for low carbonation and giving the beer a really hard/foamy pour.
As for the recipe extract is going to be tough because one of the classic components of the style is some flaked barley which needs to be mashed with some enzymatic basemalt. Roasted barley is going to give you the color, and it can be steeped.
Here is a thread with an all-grain recipe:
http://www.homebrewtalk.com/f12/murphys-irish-stout-clone-94434/ you can swap out the pale malt and flaked barley for enough pale extract to hit your gravity. Adjust the hops for your boil size and AA% (any English variety will be fine since it is just for bittering). I'd ferment with US-05 to ensure complete attenuation of the extract.