Actually, you can do both.
To search for multiple file types, type something like '*.bat;*.html' in the search box.
To save the search critera, click File|Save Search. To save the results of the search, make sure that Options|Save Results is checked, then click File|Save Search.
There may be a way to save the results as a text file, but I'm not aware of it. I usually just cut'n'paste if I need something like that.
--Chris
e-mail jcwren