Don't fret about the substrate. Most plants will primarily take up nutrients via the water column so making sure you're dosing adequately there is your primary concern. Swords tend to be heavy root feeders, and if you see your swords is 'hungry' go ahead a place a root tab under it. The very few times I've used tabs, I've broken them up and placed it in a circular fashion under the targeted plants. Seachem's root tabs are a good product.
For CO2 check out fire extinguisher outlets, welding supply stores, and even home brewing outfits. It's true that once you switch to pressurized you will wonder why you didn't do it earlier.