For the sake of the discussion I'm using the absolute worst case figures, filling from completely empty dry tanks to 100% and the fuel capacity figures for the 747-8I from Wikipedia (it looks to have the largest fuel capacity of the 747 family).
Fuel today in Brisbane will set you back $1.6592 per litre of Avtur, so it will cost $403,385 to fill up 243,120 litres.
Using the quoted figure of an increase in excise from 3.556 cpl to 9.53cpl gives a change of 5.974 cpl, and the total cost goes from $403,385 to $417,909 - a change of $14,524, or 3.6%. With fuel being a proportion of the aircraft operating costs, the actual aircraft operating costs will increase by somewhat less again.
Realistically this scenario will never happen with fuel uploads being significantly less than the complete tank capacity every time - you'll never fill from empty (I hope!), and rarely fill to 100%, so the actual cost will be a fair bit lower. So in answer to your question NN - not very much! The numbers are big, but the proportions are small
