Check Engine Light Came On.....

[jelly53]

Today while I was driving the engine light came on and then the engine started shaking very badly, especially when I tried to push the gas pedal. checked the code out and it said "Cylinder 3 Misfire", I been meaning to do a tune up on my corolla, but I didnt think it would be this quick.
I bought some NGK-IX IRIDIUM plugs from auto zone and plan on buying the rest of the parts from the dealer.
Also the engine light stays on for a bit, and then it starts to flash on and off. Whats up with that?

[jelly53]

UPDATE: I replaced the plugs, wires, dist cap/rotor and now the car runs way smoother then before. The engine light turned off right away. However, I was having trouble taking out the FUEL FILTER, it seemed to come loose but wouldnt come off. I'm afraid of stripping the bolt, so I will just let some mechanic to do it for me. My corolla has METAL PCV valve, and someone told me I dont have to replace it unless in breaks. But i'll go ahead and replace it anyways. The dealer didnt have in stock, so I ordered it.
Total Price so far around $240.00