ZIG,
You cannot live decently and save money with 3700 QR per month even if you are single.Life,accomodation are very expensive in Doha.
To give you an idea, the rent for 1 correct bedroom fully furnished is around 5000 QR/Month.
I suggest you to discuss frankly by phone with one the phillipinos who is using this forum,you will ask him all the questions.
Good luck and take care