XBMC.RunScript can execute only python script I think. I think the best would be to rewrote above script to python. To copy file use How do I copy a file in Python? - Stack Overflow and for notification xbmc.executebuiltin('Notification.
Maybe something like
Python
#!/usr/bin/python
import xbmc
from shutil import copyfile
copyfile('/storage/.kodi/userdata/bkpmaps/numbkeyboard.xml', '/storage/.kodi/userdata/keymaps/keyboard.xml')
xbmc.executebuiltin('Action(reloadkeymaps)')
xbmc.executebuiltin('Notification(Kodi Info, Keyboard Disabled, 7000, http://powerpi.de/wp-content/uploads/powerpi/powerpi_ambi_thumb_off.jpg)')