Few translations or critical Latin editions will surpass C.W. Keyes' work for the Loeb Classical Library edition of Cicero's De re Publica and De Legibus (Harvard University Press, 1928).
Alternatively, Niall Rudd's translation (Oxford University Press, 2009) for the Oxford World Classic's series acts as an excellent and more modern version of the English.
Secondary Texts
Works on Cicero
In Cicero: The Life and Times of Rome's Greatest Politician (Random House, 2002), Anthony Everitt looks into Cicero's extensive and engaging involvement in Rome's constantly shifting political landscape.
Katharyn Tempest's Cicero: Politics and Persuasion in Ancient Rome (Bloomsbury Academic, 2011) offers a recent and more scholarly approach to the great orator's life.
Edited by Catherine Steel, The Cambridge Companion to Cicero (Cambridge University Press, 2013) provides a fantastic scholarly introduction to Cicero's life and work.