31 Grand is fine to live with the family.. today you can find nice fully furnished 3BR flat for about 9,000. car will cost you around 2500-3000, food+household for family of 3 is another 2500-3000. The rest is up to you: to spend on clothes, to spend on travel/outings, to save it, to donate it.. :)
welcome to Doha.
Chinese community is not too big, rather very small.. at least comparing to chinese community in Toronto :):)