Here's a tutorial about converting Penumbra models to Amnesia:
http://www.frictionalgames.com/forum/thread-5126.html
Regarding your light bulb idea, here's a script that should help you:
void OnStart()
{
AddUseItemCallback("uselightbulb", "lightbulb_1", "AreaUseLightBulb", "OnLightbulbUse", true);
}
void OnLightbulbUse(string &in asItem, string &in asEntity)
{
SetEntityActive("lightbulb_lit", true); // make sure it's not active in the level editor (same for the light)
SetLightVisible("PointLight_1", true);
RemoveItem(asItem);
}
lightbulb_1 = the light bulb in the players inventory
AreaUseLightbulb = the area that the player uses lightbulb_1 on
lightbulb_lit = the light bulb that will show in the level
PointLight_1 = the pointlight that creates the light generated by lightbulb_lit
Alternatively, you can just attach a point light to the light bulb entity in the model editor.