I would switch the incandescent bulb out for a 6500K (Daylight) compact fluorescent like this:
Just make sure your light fixture you can handle the wattage of the bulb you replace it with. You should be able to grown any hardy, low light plant with this in a 2 gallon tank. Some plants I have kept successfully:
- Marimo Moss ball
- Java Fern
- Java Moss
- Cryptocoryne Wendtii
- Dwarf Sagittaria
Make sure you get different types of plants, i.e. some that float and some that root into the substrate.