You need to book a connecting flight so you can stay airside and not go through immigration. It may cost a little more but you can avoid all the Thai Pass crap.
Visas can only be obtained out of Thailand with the exception of a 90 day O visa based in retirement, marriage,etc. You cannot get a tourist visa inside Thailand.
You're asking immigration about an extension when you still have a valid visa. If your visa is still valid then you can leave and re-enter and get another year. You'll need to meet the entry requirements but the financials were required to get the visa and you don't need to do anything about them now. You'll need insurance like you did last time you entered.