That's one of the map lights. What we generally call the dome light is the one over the back seat. I'm not sure if the switch itself can be replaced--it seems like it's molded into the assembly. Here's the part number for the whole assembly:
LAMP ASSY, MAP 81260-42011-B1
If you Google that number you will find many Toyota dealers selling the part for around $92. Very easy to replace, plug and play, snaps right in.