Two of the following are from Australian authors and are good:
Critical Theory After Habermas Encounters and Departures Edited by Dieter Freundlieb, Wayne Hudson and John Rundell
Mostly consists of already published papers in Critical Horizon but some have been revised for this edition with a noteworthy introduction.
Dieter Henrich and Contemporary Philosophy
The Return to Subjectivity Dieter Freundlieb
First book legnth lucid introduction to Henrich in English but half of it is really about Habermas Henrich debate. Shows the importance of Habermas for the contemporary philosophy.
Habermas, Nietzsche, and Critical Theory
Contains important article by Max Pensky and Habermas' "Nietzsche and Habermas's discourse of modernity -- Postscript from 1968 : on Nietzsche's theory of knowledge"
Contains an article by Habermas.