seeing that your first response was ussless as dog crap on a stick I will attempt to help you out. as far as I am aware no one makes the GTO front to suit VY guards and headlights.
effectivly you will need to change the headlights, guards, bonnet, lower windscreen plastic panels. not a big job but expensive. When jason grey changed the front on his monaro (STREET) that set him back in the vicinty of $2400 for parts.
you could just change the guards and headlights but the bonnet wont line up properly.
if you are still keen however I would suggest JHP.
JHP Vehicle Enhancements - Specialise in Holden Monaro and Commodore Spoilers, Body Kits, Tyre and Wheel Packages. would be a good place to start looking at getting a GTO front bar