If you're not planning on adding CO2 you should aim for about 1.5 Watts per gallon, for a CO2 setup at least 2 Watts per gallon, so you will need to upgrade your current lighting.
You can either do this by adding more T8 lights with a separate T8 controller or T5 lights have higher power ratings.
Make sure you get plant growth neon tubes and reflectors as well.