Is central retinal artery occlusion correctible, and if so, then how much time do you have?

Not correctable . Occlusion of the vessel can occur from a plaque, clot, emboli, irregular heart beat, etc. Eye can worsen (glaucoma/pain) even if vision improves some, which is rare. The important task to do is to prevent more events in eyes and brain, see your family doctor to determine what caused this occlusion.
No good treatments. There are no scientifically proven treatments. If you have one though, you must be worked up for embolic disease (carotid ultrasound and echocardiogram) and you must rule out giant cell arteritis.
Not Correctible. A central retinal artery occlusion is not correctable. While the vision lost is usually permanent, some improvement may occur with time. Be on the lookout for signs of neovascularization. This can cause a very painful type of glaucoma. While the vision is not correctable, things can get worse....See your eye doctor.