If you're not yet married and entering on visa exempt you're cutting it a bit fine. You'll get 45 days + 30 (extended). Why not apply for a tourist visa? Do you already have a bank account in Thailand? It's possible to get one on TV but some people have experienced difficulty.
Once you're out of quarantine I'd head out straight to the immigration office you plan to use and ask them for the hand out. All requirements are similar but each are different. For the money it's 2 months before and to be kept in the bank whilst under consideration (some immigration offices differ). After that you can use the money as you see fit.