back up to a wired idf switch

Hi folks,

Long story short, I've started a new job which has me doing things I haven't done in a long time (10+ years) and need to ask fellow techs a pretty silly question, I feel anyway.

I have a bunch of computers about 500m away from my servers wired through ethernet to an IDF switch that is fiber to the servers. I need a back up solution in case the fiber is down, someone cut it last week and it was a nightmare. I have a wifi network that reaches these computers but they don't have wifi cards. What I would like to do is connect the switch at the idf by ethernet to a wifi bridge/hub/repeater/whatever that is connected to my existing wifi network back to the servers.

What is the best way to go about doing this? Am I going about this the wrong way. I do not want to add more wires back to the server room. It's a manufacturing environment and it's a already mess. We also can't replace the computers or add wifi cards to them as they are specialty computers, not your average desktop.

Thanks!