You have 2 choice;

Choice 1: Buy a Wireless Router and connect it to the ethernet port of the Qtel ADSL Modem.

or

Choice 2: Buy a Wireless ADSL Modem Router and connect direct to the telephone wall socket. Remove and keep the QTel Modem.

The choice i would go for is No. 2, as these days a Wireless ADSL Modem Router will cost less than QR 300.00.