I recently had to hunt and hunt for a lighted hood for my 5.5 gal and finally found one at Jack's Aquarium & Pets; it's also an Aqueon. In looking at the Manual I noticed that they have light strips (replacement) for a 2.5 gal. You might look into whether that would work for you, I think they will also just sit on top of the glass.
Also, if you find a place that sells Aqueon hoods they might be able to "special order" one for you.
Oh, and if all else fails, you could just set a lamp next to the tank for light. Many are tall enough to reach over the top of the (cute little!) tank to provide light for your fish.