The problem in Bangalore is not getting an apartment to rent. The problem is 'advance'. The amount you have to pay in advance can be as high as Rs. 50,000.
Apart from advance, 12K is good enough for one to survive in Bangalore, depending on the area. Areas where there's a lot of demand for accommodation, student population is high (Vasanthnagar) or if the area is 'happening'(Indiranagar), apartment rates are soaring. In Vasanthnagar, PG accommodation rates start from Rs. 5,000 (without food), leave alone apartment rates.
It's advisable to stay in an apartment comprising of a hall, kitchen and bathroom. If interested, you could stay in a 1 bedroom flat and rent out a portion of the hall/ share the flat with your colleagues. You could also stay in a PG that provides food. Sharing/PG are the best options available.