Sorry to hear your bad news, i just rebuilt my whole engine once this past summer and now i have to put a new top end on it because my asshole step dad wanted to half ass it and not do it right. I recommend taking it to the shop and getting it done like one of the guys above said. They will tare it down and tell you the damage / costs. Or if you know someone who could guide you, you could do it yourself and have a good learning experience.