What size/type of bulb is it? I have had success with both Amazon and Ebay for LED replacements. Just type the size/kind of bulb + LED.

There are also aftermarket dome lights that are LED to start with.

http://www.amazon.com/Gold-Stars-F3528001-Fixture-Natural/dp/B00CZCY5SE/ref=sr_1_6?ie=UTF8&qid=1415831819&sr=8-6&keywords=led+dome+light