Post a screenshot so we can see better what you are describing. In any case go change your Wifi password - 10 characters min include capital letters and numbers - randomize it or at least don't use anything like proper words - no 'h4k3r733t' words either! Make sure WPS (wifi protected setup) is turned off on the router: some implementations are easily hacked remotely. Double check that you are using WPA2 only.
Second - are you on BT?
Third: just occurred to me that you may have bluetooth switched on on your PC - are these bluetooth devices that are being seen?