Formula Help: display text if Cell (date) is within date range

Hi
I am looking to do the following:
B4 is (expiry) date
B5 to display text "6mths" if expiry date is within 6-3 months from today
B6 to display text "3mths" if expiry date is within 3-0 months from today
B7 to display text "expired" if expirty date is today or a date in the past.

I have written the following formula, but receive a #value error:
=IF(AND(MONTH(B4)-TODAY()<=6,"6mths"," "),IF(MONTH(B4)-TODAY()>=3,"6mths"," "))

Any ideas?


Harvey