There are, in fact, several different English translations. I have heard the one with the second hail in it, but that is not the most commonly used version, probably because there is no second salve in the latin. It is important to remember that the original prayer Salve Regina is in Latin; all else are translations.
Salve, Regina, mater misericordiae;
vita dulcedo et spes nostra, salve.
Ad te clamamus, exsules filii Evæ.
Ad te suspiramus, gementes et flentes
in hac lacrimarum valle.
Eia ergo, advocata nostra,
illos tuos misericordes oculos ad nos converte.
Et lesum benedictum fructum ventris tui,
nobis post hoc exsilium ostende.
O clemens, O pia, O dulcis Virgo Maria