Im new to the model train world so i need some help. i recently acquired G scale bachmann New York Central Passenger car. I have been trying for months to repair it, taking it to hobby stores and even calling bachmann themselves about it, but to no avail. so i opened up the car myself and took a look inside and found that the bulbs are blown, can anyone tell me or at least guide me on to replace the bulbs? i really want this train working for Christmas, and i already sent the engine to repair, all thats left is the car.

i believe the car is a 3rd generation car

Im kind of new to repairing trains and cars, since its my first one.

the locomotive is a bachmann 4-6-0,  with passanger car (1)

its about 20 years old (give or take a few years)
i need to know how to change the locomotive headlight and where can i purchase a new bulb for it

i also noticed that on one of the driving wheels, the pin holding one of the coupling rod/side rod to the drive wheel is missing
and im wondering if anyone knows where to buy and how to install the pin or if i need to send it in for repair

and for the passanger car, i need to know how to replace the lights on top the car and where can i buy them , ive tried but i dont want to risk bursting the wire or breaking something, so a little help will be well appreciated.

p.s. does anyone know where i can buy large curve tracks?