Complex sentence: Along with the album, Cousins toured the US in Spring 2008, (joined by Ian Cutler for the early part of the tour), a concert album from this tour, entitled "Duochrome", was released in September 2008.
Split into simpler sentences: Along with the album, he toured the US in Spring 2008 (joined by Ian Cutler for the early part of the tour). A concert album from this tour, entitled "Duochrome", was released in September 2008.