Two renormalizations of the electron propagator are introduced. The first adds ground-state correlation corrections to superoperator Hamiltonian matrix elements between shakeup (two-hole-one-particle) operators. The second replaces Hartree-Fock orbitals in the reference determinant with approximate Brueckner orbitals generated with coupled-cluster theory. Formulas for superoperator matrix elements that apply to both bases are presented. Calculations on electron detachment energies of molecules and anions show the predictive superiority of the method that adopts both improvements.