Local petshops may sell Malaysian driftwood. Here it is almost always sold with plants attached. Malaysian is the dark stuff.
Your local council should be able to tell you the hardness and pH of your water. :) I got my information from my water authority website, then confirmed it with my test kit.
It is pretty important. Although it isn't going to instantly kill your fish, keeping soft water fish in hard water and vice versa will cause problems with their internal organs and shorten their lifespans. For instance, I can't keep livebearers unless they are locally bred in local water, or add coral to my water to harden it, because it is super soft.