Legally, you're not supposed to do anything although covering them back over is probably okay. The thing is, the raccoon or whatever predator knows where they are and will be back to finish them off. You can make a new nest as you did with dirt/sand from that area. Don't bury them too deep because they need some air exchange. The depth the mother buries them is to regulate temperature and hide them from predators. My site has a little bit on hatching eggs at
http://www.fishpondinfo.com/turtles/turbreed.htm#hatchThe eggs do need some moisture. Mist them a few times a week but not heavily.
My page on hatchlings including snappers, legalities, etc. is at
http://www.fishpondinfo.com/turtles/hatchling.htmIf you get some to hatch, you should release them right away, or you'll become attached!