Possible Duplicate:
How to get expiration date and flags associated with a cookie from Internet Explorer?
How to get expire date from cookies file
my cookies likes this:
UserInfo
6pzYKskEcx7lflixFLGmBhv4+SUOt+G75z0ASsu91SzDPS0WfW4Q+7nud+ljldfEuDotv86J6gcG+ZX7qNFRFNGeH1wt7Y3XkRuRwUH7xh69fcsoePvz8fBITBM0qpnj3iOoD4bOOJ/fdAhbZ7aTlEhx0lTV4ZLyBXeras944F7FtAYxiU/let4x9U8rB+2R
127.0.0.1/ 1024 3442423040 30339635 729453404 30267216
*
Gets or sets the expiration date and time for the Cookie as a DateTime.
http://msdn.microsoft.com/en-us/library/system.net.cookie.expires(v=vs.80).aspx