I'm not sure exactly how the Argentinian government works, but I know it's an electoral democracy like most industrialized western nations, so the way people vote must matter in some meaningful way.

Vote for pro-choice candidates. Urge others to do the same. Urge the elected politicians to advance rather than regress the cause of womens' autonomy and governing according to secular, rational priorities.

I personally think the church needs to stay out of politics. No one has ever been able to give me a secular reason for why a woman should not be allowed the option of abortion, and gay marriage for that matter. Religion should be a private thing not something forced down the throats of everyone else. If one doesn't want an abortion, don't get one, but do not deny someone else their option to choose.