I did EAD by myself. You need to renew EAD 90 days before the expiration date. Just fill out the form(I forgot the form#. the immigration officer gave it to me) and mail it to BCIS. If you do not get it after 90 days, you can walk in the local office and get it right away( well, pretty much depend on which local office you will go. I heard in New York it is a nightmare. The total time I spent was about 4 hours in my local office.) You definitely need the copy of I485 receipt.
I do not know how to renew or reapply AP. The lesson I learned is if you go to a local office and consult with an immigration officer, he/she will kindly guide you through every steps. So far I have positive experience with local BCIS even though the center is very slow.
Good luck