Ouch, I've been there. If you forgot to save in the town square before updating, the only thing I can think of to try would be manually backing up your save before uninstalling the game and reinstalling the version that your save belongs to.
Sorry I didn't reply sooner, I actually had a save slightly before that one that actually works which is in the town square. Which I'm grateful for my own stupidity to have several saves (as you can see on the pic) tho the one save in the church I bet it won't work but I'll try it either way.
Edit: the last save that actually worked... took me back to before i could get the first sigil ;-; i have to redo the forest dungeon, which actually took a lot of time
Ah, I guess I'm just surprised you don't make a habit of saving in the town square after every significant event/dungeon, what with the sheer amount of updates this game gets on a regular basis. You'd have lost your save long before ever making it to the Will/Power Temple if you forgot to save in town square THAT often.
Still, try to back up your saves before you uninstall the game so that when you reinstall the version they belong to, you have something to get back to town square with rather than starting over. Trust me, you don't want to be caught out every time you update your game.