Rotation of a dipole in a uniform field

A dipole with $p=3.0\cdot 10^{-12}\mathrm{C}\cdot \mathrm{m}$ is in a uniform field $E=4.0\cdot 10^{4}N/C$. Compute the maximum torque of the electric forces on the dipole and the work that an external agent must do to rotate it slowly from the position of stable equilibrium to that of unstable equilibrium.