If the house was transferred to your ex, it counts as a gift of property from one spouse to another, not a sale. The basis remains the same as when you both owned it. You have nothing to report.

If your ex subsequently sold the house, it is not your sale, it is hers, and she needs to report it.

If you purchased the house in 2008 and got a First Time Homebuyer Credit, you are no longer responsible for repaying the credit. Your spouse assumes full responsibility for the remaining balance.