I have a few thoughts:
Charge up the Kindle. Wi-fi may not work so well if the Kindle battery is low.
Take it home and reset your router. I can rarely get my Kindle Touch to connect without resetting the router, though it usually can find the signal.
It could be a hardware problem, but the fact that it has worked previously makes me doubt it.
Restoring your Kindle to factory defaults will not remove your hacks. If you choose to restore it, the hacks will remain, and all of your books and settings will be deleted. Will it help? It could. No reason not to give it a try as long as you have all of your books backed up.