As she continues her Italian tour, President Cristina Fernández de Kirchner tried to seduce Italian businessmen into investing in Argentina, adding that her trip meant a “restart” of the relationship between both countries.

“Come to Argentina, come to know us,” she told the businessmen. “You will find that it’s a good place to live and invest in,” she added, as she highlighted the coutnry’s recent economic growth.

'country', I'd also say 'she told business leaders on X day', rather than 'businessmen', which isn't a word used often as a title in formal situations.

The President also met with Italian Prime Minister Silvio Berlusconi at the Chigi Palace in Rome.

Fernández de Kirchner began her official visit to Italy by meeting her Italian counterpart, Giorgio Napolitano. The meeting took place at the presidential offices at the Quirinale Palace and lasted over 45 minutes.

'in the' instead 'at the' twice. i'd use 'lasting' instead of 'and lasted'

Also present in the meeting were Foreign Minister Héctor Timerman, as well as Planning Minister Julio De Vido, Agriculture Minister Julián Dominguez and Human Rights Secretary Eduardo Luis Duhalde, among others.

'along with' instead of 'as well as'

“I am from Spanish descent, but I’m my country, if you’re not from Spanish descent, you’re from Italian descent,” she told Napolitano before the press. With a smile, the Italian president said he appreciated her words, and then led her to his office, where they met in private.

'said that', the last sentence could use refining, 'and then led her inside his office for a closed-door meeting.'

The President flew from Mexico to Rome on Tuesday in order to take part in the celebrations of the 150th anniversary of the Italian Unification, to which about 40 heads of state are expected to attend on Thursday.

I'd change to:

'The President flew from Mexico to Rome on Tuesday to take part in the upcoming 150th anniversery celebration of the Italian Unification, scheduled for this Thursday, in which the attendance of around 40 various heads of state is expected.'

Seemed staggerred before, action by the focus -> time -> event -> timing of event -> description of event.

Her visit marks the beginning of a new era in bilateral relations, since both countries had clashed several times since 2002 despite being the country with the largest percentage of Italian descendants in Latin America.

since doesn't work, 'as both countries had clashed several times since 2002'

At the same time, Foreign Minister Timerman met with his Italian counterpart, Franco Frattini, and signed a document in which Italy promises to make available any files in their embassies and consulates with information related to the latest military dictatorship.

'During this time', and I wouldn't stagger the point, 'Foreigner Minister Timerman and his Italian counterpart, Franco Frattini, signed an agreement that will make available any Italian consulant files or documents holding information related to the last military dictatorship.'

'latest military dictatorship' sounds like a pessimistic argentine's freudian slip :)