awwh I really have no advice or suggestion on what you can do to keep the place snake-free! I hope that one you found was the one and only (no more), but I would be also worried if I were you.
This is scary! Snakes scare me! I must be honest and say that: snakes, scorpions and crocodiles are few of the creatures that I do not fancy! They seriously scare me!
Some people raise snakes as pets, but I really can't imagine myself with one. I was at a store that sell pet products a couple of weeks ago. In the corner of that store, there were snakes for sale. I didn't know that the store sell them and was not aware that they were at that corner. The second I laid my eyes on them in that corner, I jumped in fear and left the store as fast as I could. They say that these snakes are harmless, but I don't know why they still scare me!
I really hope your place will have no more snakes.
Good luck!
Kat