If I understand your question correctly, you can only use miles for upgrade to go to the class above the one you have booked. Therefore you need to buy a Club World seat to upgrade to First. It would be, I believe, 50,000 miles for this.
It hasn't been possible in the past to (say) upgrade from World Traveller to First by using 100,000 miles, and I don't think that this has changed now.....