How to Increase 1 month GPRS VALIDITY oF any Data pack for DOCOMO

Dial *141# - select internet option - n then act pay per sitelike facebook, orkut, etc then u will get 1 month valadity for facebook or orkut with 220mb.
N extra 20 mb for any site browsing.
NOTE:- if u hav 3G compatible handset than u get 3G SPEED