Well, it Depends Actually. If you activated it Right When you got it Last Month, Then you Would Only Have one Month Left Of Membership. however If you activated it Pretty recently, you Would have 2 Months of Membership.
Basically, Say If I Used a 2 Month Membership Card, May 11th, then Today, June 11th, Would Have 29 Days of Membership Left. (Because there are 31 Days in May and 30 Days in June.) Meaning if today Is June 11th, and there are 29 Days Left of membership, it would Last until July 9th.
It will add 2 months to your membership, so if you had no membership when you redeemed it, you will have 2 months from the DAY you added it. If you had a membership when you redeemed it, it would take on 2 more months to your existing membership.
Karic 
