During nova outbursts the decay of (18)F is the main source of gamma-ray emission at and below 511 keV. In spite of much experimental effort, the quantity of (18)F synthesized still suffers from large uncertainties which arise mainly from the (18)F p, a)(15)O reaction cross section at low energies. We report here on a new direct measurement carried out at the Louvain-la-Neuve RIB facility of Louvain-la-Neuve using an isobarically pure (18)F beam impinging on a thin polyethylene target. Cross sections down to a center-of-mass energy of 400 keV have been obtained and the results together with previous experimental data were compared to R-matrix calculations. The effect of the relative contribution of the two low-lying 3/2(+) resonances as well as the sensitivity of the calculations to the R-matrix radius is studied in detail.