Re: Please correct my cover letter
Your potential employer does not want to hear that you are finding out about their job by accident.
They don't really care that you like them; they want to know why they will like you.
You do not "drop by" an office to see if they will tell you more about the position.
Please visit a few job posting sites and review their sample cover letters. I'm sorry to say that yours would have been thrown in the recycle bin the moment I saw you found us by accident.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.