1. Re start again by leave Thailand and apply new oa visa.
2. Continue showing 800k for the latest 3 month. By keep 800k for another 2 month and pay overstay 500/day from the date that visa already expired until aniversary of 800k for latest 3 month period. Then, go to extend oa visa and pay penalty. Please remind to not overstays for 90 day, you will prohibited to enter Thailand in case over 90 days.
Basedbon my understanding, you need to contact local immigration office to get the extension stamp from them. Then, they will extend the visa for you with the wording explain that you are overstays but exempt per government annoncement. You would be able to stay more 30 day and may extend again with the letter from Embassy.