Slater integrals are two dimensional radial integrals whose integrand is constructed from normalized eigenfunctions of the Schröodinger equation. These integrals occur in many atomic structure and scattering computations. However, in 2-dimensional R-matrix propagation they represent a significant computational bottleneck. The problem involves two steps: numerical solution of the Schröodinger equation followed by computation of the Slater integrals. By exploiting the oscillatory nature of solutions of the Schröodinger equation we have devised a two stage computational strategy where the second stage is influenced and informed by the first. In particular, we have developed extended frequency dependent quadrature rules (EFDQR) that both improves the accuracy of the integrals and results in a performance gain of over two orders of magnitude.