A decent life style will cost you as follows:

Grocery..... QR. 3000/-
Mobile ..... QR. 500/-
Satellite TV.QR. 150/- (QR 1000/- Installation Approx)
Dining Out/Entertainment... QR. 450/-
Car's Installment. QR. 1800/- (Five Years Plan for Nice Saloon Car)
Water & Elect..... QR. 300/-
Car's Fuel etc.... QR. 500/- (Including Maintenance)
Total = QR 6700/month.

Keep in mind that Children's Education is quite expensive here... Try to include this expense in your contract before coming, if not provided.