You did not mention how much you will be getting for you housing allowance. My advice you should asked the company to provide you with housing during your stays in Qatar.

School for english curriculum you can go to Doha College, i heard that park house will opened secondary school but have yet to realized.

Gazoline cheap here. Around 0.80 riyal a liter. I have no idea how much is it in your home currency.

Tap water not drinkable ...

Hope this helps.

Good luck :-)