You probably have between 40 and 50 PAR light intensity at the substrate. That is about where you need CO2 to get good healthy growing plants, without serious algae issues. An "upgrade" in lighting would make it essential that you have pressurized CO2. So, I would add CO2 now, rather than increase the lighting. There aren't a lot of plants that won't grow with your current lighting, if you do use CO2.