AddAll is your friend Rafal. You can get several used copies there. I am using them to find out of print and used books all the time:
http://www.addall.com/New/compare.cgi?dispCurr=CAD&id=266337&isbn=9780471022 282&location=11000&thetime=20130320071518&author=& title=&state=AK


Oh, now I've noticed they sell both volumes separately, so it is not so cheap after all. Good luck!