Coordinate axes switched by mistake

I build a scene from a image. Sadly in the building of the scene by a mistake I switched the x - y coordinate (I thought that the origin is on left top side of image). Now the scene is like a rotation with 90 degrees left and a horizontal flip of initial image.

I am thinking that if I will rotate all scene and flip it back this would repair my mistake.

Could you tell me how could I do this rotation? I will apply this rotation to the root node?

Thank you