There is a software router called connectify that can be install on your PC. This is assuming your IT staff are s and you guys have admin level access to your work PC's and can run installs. Add a usb wireless nic to your PC and set it up to not broadcast a SID and set up WPA2 security. That should work. But again this is assuming your IT staff sucks and are not serious about security.
I have played with software routers in the past... that is an interesting idea. Thanks!