Yep, Im running a GF FX5200 128mb as well and it works great.  I get around 60-70 FPS in the air and 40 or so near the ground.  Then again, I also have a 3.2GHz processor and 2gigs of RAM, so your's (Eagle) will very much differ.
Id go with gunner and just try it out.  If it doesnt work, look into a new video card.  If you're on a budget, I'd go with the Fx5200.  Its fairly cheap and will run AH2 no sweat.