permit letter

hello good pm.
please help me to correct my grammars.this is my letter that I will address to our dean.

Madam:
I, Sherwin Yu, a BS Mathematics 4th year student would like to ask permission from your good office to allow me to cross enroll at the education department. I was being advised by our department to take the Plane and Solid Mensuration this semester. I was enrolled in the old curriculum and the said subject is not offered in the new curriculum. I inquired at the engineering department but they offered 2 units only for this subject in which I cannot avail because the subject I have in my prospectus is equivalent to 2 units. The BSed Math course has this subject that is equivalent to 5 units. Our department said that it is okay to exceed 2 units in this subject. So I will take this subject at the education department.
Thank you for your cooperation.

Respectfully yours,
Sherwin Yu

If you have any suggestion/s to revise this letter please comment your suggestions.thank you:)