The "wings" are pretty generic. You could buy two single gang boxes (2 wings each) and transfer the 3 wings you need to your box.

And, it should be obvious from what happened, but don't drive the screws so hard that the wings break off or the drywall gets crushed! Just snug... Not the place to try out your new Christmas impact driver!

You will have a minor problem mounting your light fixture - some want the mounting holes to be in one location (vertical or horizontal) and some have rotating mounting plates that don't care how the box is oriented. If you have the first type, rotate the electrical box 180 degrees - since it has three wings, that should give them all some drywall to attach to. You might have to turn the power off and loosen the wires. If the light fixture is adaptable to any angle, then you have nothing to worry about...