The "remedy" rhetoric has about gone off the rails at this point, but let me propose four ways in which devotion to the Rosary produces effects that in some measure counter the vice of anger.
(And, as you remember, anger is a desire for vengeance that is sinful either because the revenge itself is unjust or because the desire is unreasonably great.)
First, the simple act of praying the Rosary is physically calming, and when you are calm you have farther to go to become unreasonably angry.
Second, praying the Rosary daily extends this physically calming experience through time. If you are calm and still every day for fifteen or twenty minutes, it will be easier to be calm and still at other times of the day.
Third, praying the Rosary affords an opportunity to bring your anger to Jesus and Mary. St. Paul's advice is, "Don't let the sun go down on your anger." You could anticipate sundown and say, "Don't let the fifth mystery finish on your anger." The time spent praying the Rosary can cool your anger down to a more reasonable zeal.
Fourth -- and more spiritually -- the Rosary has long been proposed as a prayer for peace. As the blessed Pope John Paul II wrote:
... to rediscover the Rosary means to immerse oneself in contemplation of the mystery of Christ who "is our peace", since he made "the two of us one, and broke down the dividing wall of hostility" (Eph 2:14). Consequently, one cannot recite the Rosary without feeling caught up in a clear commitment to advancing peace....
That "cannot" may be more of an exhortation than an observation, but the experience of the Church is that the Rosary fosters peace. As recently as this past Sunday, Pope Benedict XVI said:
We also desire to welcome the Virgin's maternal request [made at Fatima], committing ourselves to saying the Rosary with faith for peace in our families, in countries, and in the whole world.
If we come to the Rosary with an intention for peace, and for overcoming anger, our prayers will surely be heard.