If you are 70 years of age or more, you can use a special channel through Immigration, which is not taking so long. Just identify yourself as "Poo sung aju" to the staff.
Yolu can apply for a 1 year visa, if you're older than 50 years, in your home country. Then you need a bank account in your home country, which should not be a problem. Check the conditions to apply for a "O-A" visa on the web site of the Thai Embassy in your home country. Good luck.
Then go shop around for the service fee they charge. Differnt agents charge different fees!
And make it clear, that they should do it at the place, where you stay, not in another province. And that you expect them to process the whole thing within one day!