Userform: insert multiple lines by text value

Dear all,

I am stuck with one function in Userform... I have two Combolist which help me to define the period.

Eg. From Jan-13 To Jul-13
and then there is a "Add" function... My ideal function is by using "Add" button, we will insert 7 rows as each represent one month... the rest of the information will be the same but only the month column will be different from others which will be" Jan, Feb, Mar, Apr, May, Jun and Jul"....

Any idea of how to edit the coding in the "Add" Button?? (month will be varied from jan-12 until dec-14)

Thanks In advance

Sansa