Added to readme and bugfix in import hook

README.md

@@ -29,6 +29,9 @@ As in mames' original version, you can create such a __script__ easily:
 If you have a file containing _ code, you can import it after importing
 _. Cool, huh?
 
+Please note that the file you are importing is either an `.us` file or import
+it by the fully qualified name(e.g. `import \_.py`).
+
 The idea behind it is using Pythons import hooks to achieve something similar
 to mames' original script, only that it works the opposite way.