Sony Corporation projects that the entire PSN fiasco will cost them approximately $171.2m by the end of the 2012 fiscal year. This includes both the PSN downtime and the hacks on Sony Online Entertainment's website according to their report to investors:
Based on information currently available to Sony, our current known costs associated with the unauthorised network access are estimated to be approximately 14 billion yen in the fiscal year ending March 31, 2012.
Sony predicted a profit of ¥70 billion in February, but with the Japanese earthquake and tsunami along with the PSN hack, they now see a net loss of ¥260 billion for the entire 2011 financial year. Wearing a coat of optimism, though, Sony expects to be profitable in the 2012 year.
[Source]