The key documents from Budget 2013 are collected on this page. (A longer list of documents is available on the Department of Finance website here.)
Minister Michael Noonan's Budget 2013 speech can be read in full here.
Summary of 2013 Budget Measures (policy changes) can be read here.
Motor Tax overview is available here.
Documents relevant to Budget 2012, including the Minister's speech, are all available at this link.