Just off the top of my head:

Villa QR 18,000/month

School - QR 25,000/year/child in primary (up 11yrs old)

Car rental - QR 3,000 to QR 4,000/month for a large 5 seater.

Maid is cheaper if you bring over from abroad - QR 1,000 to QR 1,200/month

These will be your main costs.