you are looking at a major rebuild of engine, costing loads of money, you might be able to get another engine from good scrappy, might be cheaper than refit, but you would have to ask around differant garages to get best price for rebuild or engine swap.
one of the cause's for an engine to seize is lack of oil in engine.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.