I can show you one way to speed it up quite a bit at least.
TO add a new item to an alias, simply get the file listed in the results, and then right-click on it and say add to alias.
But you know an easier way to do what you want is to create a new search folder entry specifying the folder:
D:\PROGRAM FILES\PORTABLE APPS IN HERE\FindAndRunRobotnew\my notes\t
And set it to use MODIFIER: txt
now when you type +txt it will ONLY show/search files in that directory.