Copy cell values depending on date (Month) in two files

hi all , if you can help
I have two files file a, file b, (like attached) file a is my main file , I collect my data on it monthly and I have a calculated data year to date as in file.
I receive file b every month, i have to fill some cells in file b from file a depending on the month
i need a macro to transfer these cell values automatically
for example if we now in FEB-10 i need to transfer C3,C5,N3 from file a to C3,C5,C9 in file b respectively
(with a button in file a to open file b and transfer these values)
Thanks in advance