I've been trying to grow hardwater plants for a while and it's not easy. You won't be able to have an amano-style planted tank until you use RO water and a CO2 tank - that's just the way it is.
If, however, you'd just like to have some nice plants, that's quite doable. Ceratophyllum is bulletproof but looks a bit messy, Vallisneria does best with high light but produces awesome tall grassy beds, and anubias/java fern grow slowly but look great. I've also had good luck with Uruguay swords, Salviinia, frogsbit, watersprite. Basically, try to find plants that grow in lightly brackish water, and you'll find good hardwater plants.
You might also try Najas "roraima" (actually Najas marina) - mine grows well in hard water and looks very neat.