Call someone out to repair it. May be just a broken wire to the fan & new light bulb. Worst case is it needs a new fan motor. Still a lot cheaper than buying a new stove.
Lincoln Appliance NZ, January 2010
edit
I can answer this question...
HOW CAN I FIX MY BOTTOM OVEN FAN AND BULB ARE NOT WORKING. SO, DOES THAT ME?