When i first read white smoke in ur post, i guessed head gasket. And im glad that you already know the answer so its going to be easier for you accept it.
Its kind of mid range serious job, that could take 2 - 3 days and may cost around 1500 aed to 4500 aed.
Get some good local mechanic may be two and let them test it before you start expensive repair. With dubai mechanic it could cost around 2500 aed - 3000 aed labour job, In shj it may vary from 1500 aed - 2500 aed. And i guess with Arabian automobile it might cost somehwere around 4000 aed - 4500 aed.
Dubai based: Technical garage. AAA workshop, 4x4 motors, cars dubai, a to z.
Shj based: Al bea, auto dynamics, al najoom etc.
Good luck mate.