The stall speed varies as a function of the load factor and not angle of bank. The stall speeds quoted in the POH are all based on 1g, and in testing, great pains are taken to ensure that the load is 1 g by reducing speed at 1 knt per second.
Any more or less than 1g, the stall speed will differ. Quite simply, it is the square root of the load factor. So if your clean stall speed is 50 knots, at 2g it will be 70.7 knots (1.41 x 50), at 3g it will be 86.6 knots (1.73 x 50), at 4g it will be 100 knots (2 x 50), at 9g - the wings would have come off! But if they hadn't it would be 150 knots. And at less than 1g, you can see speeds on the ASI at less than basic stall speeds. At a 0g bunt, you can't stall the aircraft as there is no load on the wings.
When I teach stalling, I demo this to the student. I get him to tell me at what speed we have seen the aircraft stall. I then tell him it's possible to fly the aircraft at a speed lower than that and demo it with a gentle wingover and about 1/2 a g getting the ASI to read less than the noticed speed. The key to this part of the exercise is to point out that there is no buffet and therefore the wing is not stalled. I then fly the aircraft in a level 60 degree angle of bank turn which should be at 2g and pull back to the light buffet noticing the speed. Another point to this exercise is to demo that the aircraft can be stalled or still flying in attitiudes other than the one we have become accustomed to.
Buffet is the only true indication that the wing is stalling - this is the key to the whole exercise. It's not the stall warner - that's only there for certification reasons and it may be unserviceable or not be installed in the first place. I know of no GA aircraft that have such poor stall characteristics that they do not give adequate aerodynamic warning.
A lot of this should have been covered by briefing if not in the air.