And as an extra refinement to the above excellent posts, the increase in stall speed will be equal to
- the square root of the 'load factor' in the case of 'g'; or
- the square root of the weight increase, in the case of 'weight'.
For example, if you are turning at 60 degrees of bank in level, balanced flight, you will be pulling 2g. The load factor is 2. The increase in the stall speed will be the square root of 2 which is approx 1.4. So if your stall speed in level flight was 60kts, at 60 degrees of bank it will be 60 x 1.4 = 84kts.
Similarly, if you double the weight of the aircraft, you will increase the stall speed in level flight by a factor of about 1.4.