QN112 and QP112 is an audio output transistor.
Try searching on these sites>http://www.1sourcecomponents.com/search/search.htm
You need to narrow your search by going to the manufacturer site.
You can also try typing the word "audio output" - try this site>http://www.nteinc.com/search/search/search.php?query=audio+outputs&search=1
Other good site to search (datasheets - here you can find equivalent components)http://www.datasheetcatalog.com/