Let me be clear. Are you confusing a valve cover gasket with a head gasket? They are very different, and replacing a head gasket is a horrible job that requires skill and probably the services of a machine shop to mill the head.
When the car overheats, in very short order the head can overheat enough to warp. That allows oil pressure from a channel up to the head to leak over into the coolant circulation channels.
Pull a sample of your coolant out of the ET with some tubing and examine it in a clear container. Report back.
It would also shed more light on the situation if you'd describe in detail exactly what happened before and after the ET failure. Where were you? How far from home? How much you drove after the fail?
Last edited by Stinger9; 10-06-2012 at 12:32 PM.