Man that sounds terrible, can the snake crawl all over the whole house from that area of the wall? In other words is it a tiny hole it cannot progress further into? Or is it a crawlway that leads through your whole house?

If it was me, I might consider tearing the drywall off and physically searching for the snake, hopefully when she gets scared she will just ball up and you can grab her. If you do cut into the wall cut up high where the snake probably wont be, then grab ahold of the drywall sheets and just start tearing downwards with your hands rather than with tools, so as not to hurt the snake.

Good luck, I hope everything works out and you get your poor snake back safe and sound...