[3] In August 2007, PSG sold Bueno to Argentina's Boca Juniors, where he played until the end of 2007, returning to Peñarol early in the following year.

For 2009–10 he moved to Real Sociedad in the Spanish second division, following the departure of countryman Sebastián Abreu who left for Aris Thessaloniki FC; on 5 June 2010 he scored a hat-trick in a 3–1 win at Cádiz CF,[4] as they eventually returned to La Liga after an absence of three years, as league champions.

In August 2010, Bueno moved to Club Universidad de Chile, making his debut against Municipal Iquique in a 2–0 away success which qualified for the Copa Sudamericana.

On the 15th he scored his first goal for the team, against Everton de Viña del Mar in a 5–1 triumph (also away), coming off the bench at Estadio Francisco Sánchez Rumoroso in Coquimbo; nine days later he also found the net against Oriente Petrolero of Bolivia, in a 2–2 home draw and 2–3 aggregate loss.

[5] However, his agent denied any transfer had occurred by saying that the player would respect his contract until 2012,[6] but he finally signed a three-year deal with the Mexican club.