I'm going to move this to Aquatic Plants. I think you may get better answers there about care and whatnot. Also, there is another thread in Plants about "carpet plant". You may find that one useful
In my experience, though, the grassy type aquatic plants are pretty high maintenance. They require HIGH light, as well as good fertilizing regime. Also definitely need CO2, not even Excel does it. I never had any luck with Micro Sword or Narrow Leaf Chainsword. I think sags are a bit easier.
a good place for plant info is http://www.plantgeek.net/plantguide.php. From that page you can search by difficulty or lighting requirement. Most species profiles have a nice photo of the plant.