Wibbly-wobbly timey-wimey stuff.
New Who's "chronology" has never been consistent. The RTD era was allegedly taking place one chronological year after broadcast from every episode commencing with "Aliens Of London" (where the Doctor lands Rose back at her estate, but a year later), but you'd be hard pressed to actually use that as a basis for a proper timeline, and there's just as much evidence to contradict it as there is to support it (even more so once Torchwood
meanders into the picture as well).
Unless an explanation is given on-screen, it's best just to ignore it.
How does Torchwood muddle up the chronology?
A 2007 episode of Doctor Who, set in 2012, makes mention of Torchwood in a present tense even though the organization was disbanded on-screen by 2009, and even Jack and Gwen's splinter group in Miracle Day (ostensibly set in either 2011 or 2012 depending on who you believe, but if the chronology is consistent then it's gotta be 2012) is not truly Torchwood but merely uses the name.
Torchwood is not by any means the only
thing that contradicts itself about New Who's 'chronology', though.