hi, if the light is a round one with the bottom half a lense, it is a license plate light you can buy for 5 bucks at an autoparts store. on mine, it is soldered in, so ya have to replace the whole thing.
as for the steps, mine is a single one and i believe yours is two steps.
http://www.kwikee.com/Asteps.html
i believe this is what is in most of ours. you might have a look at the web site for any advice.
tom