female looking for help with 96 geo metro

ok so.... to start I've spent almost a thousand dollars on this thing and at first it was reliable and cheap and now I think its going to be the death of me. Well theres a bolt broken in the engine some where and now the mechanic says that he can try and have the bolt drilled out but I might need a new engine. I dont want to part with it seeing as when it runs its great considering Im in college but maybe I should consider a new engine can anyone help? Willing to pay something

where is the bolt broken off at and what does it hold?