I'm no expert, but it sounds like you've got adequate lighting for low to medium light plants. Keep in mind that none of the lighting requirements are hard and fast, black and white ratings. I've got about the same lighting as you've got, and I've got some plants that came with "requires high light" tags that are growing perfectly well. I'm not running CO2 and I'm not having any algae outbreaks (at the moment). I've got a 4" pleco that keeps the tank algae free, and I keep a careful watch on my feedings and careful watch on the substrate to make sure there's not a bunch of uneaten food laying around.
The 6500k color bulb is good, as well. I'm running 6400k CF bulbs, and all my plants seem to grow like crazy with this new fixture. I've gotten about 2 inches of new growth on the top of my moneywort since I bought it a month or so ago.
As I said, I don't have any CO2 system, but I do have a 10" Walmart bubblewand that makes teeny tiny pinprick bubbles hooked up to a standard air pump. This helps keep CO2 at atmospheric levels and buffers against a complete dropout of CO2 which would cause an algae spike.