  We extend our previous formulation of low-energy QCD in terms of an effective
lagrangian containing operators of dimensionality $d\le 6$ constructed with
pseudoscalars and quark fields, describing physics below the scale of chiral
symmetry breaking. We include in this paper the vector and axial-vector
channels. We follow closely the Extended Chiral Quark Model approach and
consistently work in the large-$N_c$ and leading log approximation and take
into account the constraints from chiral symmetry and chiral symmetry
restoration. The optimal fit of all parameters gives further support to a heavy
scalar meson with a mass $\sim 1$ GeV and a value of the axial pion-quark
coupling constant $g_A \simeq 0.55$ to 0.66, depending on some assumptions
concerning the Weinberg sum rules.
