Theres many variables to consider,one being how long did it sit with a cylinder(s) full of water that may have rusted up the cylinder walls,is the bottom end full of water/coolant contaminating the bearings etc,did you crank it over an the engine suddenly stoped cranking from hydro lock because a few cylinders are full of water? this could have bent a rod. If it hasent been long sitting Id start by draning the coolant to remove any more leaking coolant mix before it does damage,pull all the plugs and turn the engine over a few times by hand on the crank pulley nut to purge out and water then squirt some oil in the holes and spin again if its gonna sit a while. If you can fill the engine with fresh oil leave the radiator empty and fire it up for a minute or so long before it builds any heat so it can circulate the fresh oil thru the engine. For the leak it could be a cracked head,bad gasket,any warranty lleft on it?? Cost wise,hard to say depending on damages and bad parts.
