armando8a

My SES light has being on for a while now, and the car has been shaking pretty bad so I went to Autozone to get the codes pulled. The test gave the following codes:

P1320 (I think this code has something to do with the coils)
P304 (Cyl 4 Misfire)
P420 (O2 Sensor)

My question is, do I need to replace everything from coils to sparkplugs and also the O2 sensor?? Should I replace one by one and see if maybe only one thing was the problem?
Also, should I go to Nissan or is this stuff that I can easily replace myself. I am no mechanic but I've done minor stuff like my Berk Intake, oil changes and little things like that. I hope you guys can give me some advice also about where to buy the parts at a better price.
Btw, I have a 2k SE.

If I do need to replace coils, do I need to replace them all or just find the bad one??

Any help or advice is greatly appreciated

Thanks.