New Post: How to use the folder.Search() method?

This is how you'd make the the particular queries you asked for in ImapX:

folder.Search ("AND SINCE \"1-Jan-2015\" BEFORE \"31-Jan-2015\"");
folder.Search ("SUBJECT \"Blah\"");
folder.Search ("FROM \"BillBob@gmail.com\"");

The DateTime.ToString() format you want to use for the dates is "d-MMM-yyyy", since I'm sure you'll want that info.

Hope that helps.