This is a day or two old now, but JR Hokkaido President Nojima said to the MLIT committee of the upper house of the Diet (doing my best here, not really sure about this ) that JRH will buy 28 new express DMUs and 60 new commuter EMUs by 2016. These will replace some old cars as well as provide new capacity. It will be decided later exactly how many cars will be scrapped, and what lines/areas will get the new equipment. One specific thing mentioned is that some of the new cars will be 733s to replace the 48 711s in service, all of which are to be retired by the end of this year.
http://www.hokkaido-np.co.jp/news/donai/507045.html
http://en.wikipedia.org/wiki/711_series