I have that same tank. That light will grow pretty much nothing. I couldn't even grow anacharis under it. I have moved that light to my 12" deep 10g and it's giving me very low light on that.
With that light all you'll be able to grow is anubias, java fern, and moss. If even that.
Co2 with that low light is unnecessary. The plants will not grow fast enough to need any more carbon than what is already in the water column. CO2 is really only needed when you get into medium or high lighting.
If you have your heart set on a Dutch aquascape, be prepared to spend much time researching and a good amount of money. You'll want to invest in a high output LED or T5HOs, a pressurized CO2 tank (5lb would be ideal as paintball canisters run out very quickly), and dry ferts (most people on here use the GLA package).