first of all, not to sound preachy, but buying fish you know nothign about really isn't a good idea.
okay, anywho, as was stated, you probably got two males. with a 16 gal tank and two males, youre done. no more dwarf gouramis will safely go in that tank. you'll need to be sure you have plenty of plants and a cave or two for cover and territory, as d.gs are very territorial. you'll need to keep an eye on your two, one may bully the other to the point it dies from all the stress. then again, they may be fine and stay in their own territories without much trouble. but DO NOT add anymore d.g.'s!!!!!
dgs can get stressed easily so i really wouldn't recommend any overly active fish as tankmates, cory cats are bottom dwellers for the most part, so you could go with 3-6 of those (minimum of three as they school and just aren't happy alone or with just one other). neons might just be a bit stressful on the dgs, though others ahve had success with that combo. i'd go with a non-schooling fish like mollies or platies maybe. keep in mind the 1 inch to 1 gal rule initally. just my opinion.