It used to be 12 lakh when customs duties were 75%, now it is 100% plus 50% luxury tax, so add another 75% in it which is nearly 21 lakh rupees. You may not be able to pay duties as this vehicle is NCP, and to legalise it you should better go to high court with a customs lawyer who may help you to reduce duties according to old tariff. You need documents of customs duties from same kind of Prado 2005, to show the judge that same vehicle was cleared in this much amount and you are willing to pay same. But you will have to work hard as there will be lawyer of FBR as well, better to pay him/her as well.
If you are in Rawalpindi/Islamabad I can put you in touch with a customs lawyer and probably also with some FBR lawyer.