My Toyota corolla 2004, automatic engine off

HI Friends,
I am facing problem in my corolla 2004 model, let me tell you scenario how its appear.
i was waiting for green signal on traffic signal. automatically stop my engine, then i
started again, go around 5 km, then again stop, i parked my CAR in side, after 5 mints
started again and went 2 more km.
after 2 km on my dashboard engine problem sign appear and almost 75% my staring
jam, i park again on side of the road. call the mechanic he said, need to change OIL
Filter and spark plug. I am not sure he is telling correct or not, now situation is when i
am starting my car started well but after one mints automatically stop.
Please help me.