Yes, you can apply for a 1-year extension based on being married to a Thai once you cancel your WP and extension from the company. <- you don't have to leave Thailand IF you are already on an extension.
Apply for cancellation WP and extension at OSOS, then go to the local immigration office to apply for a new 1-year extension. Go to the local office to get the latest handout for a 1-year extension based on marriage to a Thai in advance.
In case you are still on the first stamp from a Non-IB visa, you have to leave Thailand once to do the application for Non-O marriage visa and following extensions from scratch.
You apply for a re-entry permit on the current stamp you already have in your passport. You get your visa/extension first, then apply for a re-entry permit on it.
, it's too late. Sydney will stop accepting online applications with the current system as of tomorrow 9 March. if you need any official documents, you must have gotten them within the business hour TODAY...
, you will have to start the process from scratch if your extension i expired during you are out of Thailand. Get an initial Non-O visa for 90 days, then follwoing 1-year extension.