Thanks to both of you who responded and provided your valuable suggestions. I ended up going for driving test without taking any lessons as I was too busy at work. But thanks God that I passed it. My test was scheduled at Qatar driving school. I reached there at 5:30 AM and was done with license in my hand at about 11:30. The worst part was waiting so long. There were about 100 (approx) people for driving test that day. About one third of people passed.
Again thanks for your tips.