Extract date from String

I have data like this .

I want to convert this into dates in this manner -

cycle1 indicates date on the 15^th of month and cycle2 indicates date on the last day of the month.  For Dec 2013, all dates should be 12/31/2013.

For example - If String is like this - ClaimExtract_CookCHIP_201401_cycle1.txt

then date should be extracted - 01/15/2014

Pls Help