I've cooked a 5 lb bone in ribeye steak before. I would treat it like that. If you don't have cast iron skillet, get one. They're like $15 at wal mart tops. Sear all sides well on the stove at the highest heat you can get (pre heat until it smokes). Then I would go low and slow (275-325) in the oven until it's done. If you try to get your browning via a higher temp oven, you're going to overcook it well before it browns for flavor.
I think 40 min - 1 hour, but don't guess. Use a thermometer! Time recipes are invariably bad.
Mid rare you are aiming for 134 F inside, medium a bit higher like 140. So if you actually want mid rare, pull it at 130 and let it coast up with carry over heat.
Temperature, not time is key
Season it well with salt as you let the thing rest. At least 1.5 hours on the counter, basically dry brining. You want to start it near room temp.