For that much time unatended you will need to do many things. Put stabilizer in the fuel tank, replace the oil, pull out all the plugs and hose down the cylinders with WD-40 then put the plugs back. Get the car off its tires and on blocks but use the suspension points or you may tweek the frame.
For a cover it will be expensive. Get a custom fit chamois cover. That will be about $450. Then over that use an all weather tarp kinda material cover. Dont have to be custom, just get one for a full size. They are about $100. The key is to make sure the tarp like cover is wraped tight around the car and well secured.