@Jack ********
I don't know anything about agents outside of Thailand. You do need to leave after you get the full 1 year extension and then your wife can apply for the 90 day non-O trailing spouse visa. I believe this is usually done in Laos.
Then after she's down to her last month on that you go to your immigration office again to get her full extension which will match the end date of your 1 year extension.