Vee wants to know if she needs any more protection than her router to keep her safe online while she's teaching. She doesn't need to add anything to the router itself, but the best thing is to guard her online behavior and keep everything online up to date. Update the OS regularly, when available, as well as the apps. Your browser should automatically update. Also, the router needs to be kept up to date and periodically, it pays to look for an update for it. Also, change the password from default. Turn off WAN administration. And turn off UPnP (Universal Plug n Play). Turn on WPA2 encryption. It'll require a password, which is good, but make it something that isn't easy to guess.
Here are other things she can do ...
UPDATE the OS. Windows updates the 2nd Tuesday of every month. Make sure to get it updated immediately! Set the Update to automatic.
PASSWORDS. Make the passwords difficult. Easy to remember passwords are easy to guess. Use a password manager and let it generate and remember passwords.
Download software only from TRUSTED Parties!
TURN OFF the computer when not using it