With your setup, it's probably the same tank I got. First, I would get a brand new bulb if that bulb has been running for a year or more. It's best to replace bulbs in planted tanks at least once a year, and some do more often.
With the setup you have, you could do low light plants without much problems. Plants like java moss, java ferns, anubias, etc. Here'sa link to some low light plants that you might like....
http://www.aquariumplants.com/Low_Light_Plants_s/25.htm
Also, some of the plants, such as the java moss and java ferns, you can attach them to rocks, decor, ordriftwood, by tying them on with thread or fishing line. After a short time, they will attach themselves and you can then remove the thread or fishing line. Another benefit of this is you can get some of th eplants a little closer to the light as well, by tying it onto a piece of driftwood, etc.
As for dosing, in a low light tank, about all you really need to dose is Potassium. You can even dose a little Flourish Excel as well, it's just another carbon source which can be used in place of CO2 injection. And if you do regular water changes, you may not even need to dose your micros, as the water change will supply those for you. But if you plant a little heavier, then you may want to dose micros as well.
One other thing as well, root tabs. If you have plants in the gravel, place a root tab under each, like Flourish Tabs. That will give added nutrients to the roots.
And most importantly, read the Stickies on here. You will learn lots.