Switch to a lacrosse ball (you can get a pack of 3 for about $5 from Wal-Mart) and add in two things ...
1. Stair calf stretch: stand on the bottom step and let your heel hang off, controlling the stretch with the other leg. Hold 30+ seconds and repeat on the other side. Twice each side, twice a day. Best if done after rolling.
2. Neural flossing: Lie supine and extend your leg up like you are going to do a hamstring stretch, with your hands laced behind your knee. Slowly bend the ankle up and down (dorsi and plantarflex). Perform for 30-60 seconds per leg, twice daily.
Let me know how it is in a week.
