Well, I'm no expert, but the bannana trees I just bought recommend a well lighted area, lots of fertilizer and water. MAybe you might be able to add a light near the plants to assist.

If you bought it from Lowes, then it is probably the dwarf (yes there is a non-dwarf species as well). These actually do very well in pots and can grow to 7-8 feet depending on how much you fertilize and water it. I keep a dwarf Cavendish on my patio and have to water it every day to keep it growing fast. These require well drained soil AND a lot of water...so if you have it in a pot, you will want to keep it somewhere that the pot can drain (like on your porch).

It may take 1-2+ years to produce fruit in a pot and it also depends on how much water/fertilize you give it. I say 1-2 years only because it is probably a very young plant coming from Lowes. Use a high potassium fertilizer for best results - I use a 6-6-18 tobacco fertilizer with high magnesium levels and mine produce about 2 new leaves a week.