Idioms of Exploring the world of english and Past papers idioms at least of 20 years are more than enough. As for as Idioms of 2012 is concern, though most it wasn't from above mention sources, but one could easily make out there meaning and make appropriate sentences.

I will advise u that dont bother about Idioms, as they only account for 5 marks, rather concentrate on Precise, Expansion, Comprehension, Direct indirect and sentence correction.