Thai Visa

It would be easier and quicker to do it in Australia. I had mine completed in 5 weeks.

Sorry, but you cannot apply for an O-A visa from inside Thailand. Those are 12 mth visas that you can only apply for at Thai embassy from your home country. If you're age 50 or older, you can apply for a 90 day O visa at Thai Immigration in Thailand. You will have to open a Thai bank account, put 800k THB in for a period of 2 mths and then go back to apply for a 12 mth extension based on retirement. The easiest way would be to just pay an agency about 25k to 30k THB to do everything for you when you get here since you're so close to leaving. I used David Lam with TSL & Associates (first class service) in Bangkok for my last 12 mth extension since moving to BK. I've done it before by myself while living in Pattaya, but BK Immigration is just too busy for me. Also, have Express Translations, Siam Legal & Bangkok Buddy agencies, just to name a few others.

I'd never use an agent for certain reasons. OP, why don't you go to the Thai embassy in your country and apply for one? In my opinion, it's way easier to visit a Thai consulate, they're usually way more relaxed and you're dealing with citizens from your own country. 

When it's time to extend it in Thailand you must have the 800,000 baht on a bank account in your name, (no joint bank account) and it's easy to extend it for another year at your Immigration.

You'll have to report to Immigration every 90 days, but this can be done online, or per post.

  It's always very important to go there well dressed and well behaved. A visa or an extension of stay can be denied for any reason.