Hey Scott,
Simple?... 
Parsing text is an exacting business – especially when you're tying to accommodate different possible inputs.
In a case like this the smart thing to do is generally let go of the idea of writing the perfect regular expression and preprocess the text with a different regex.
Something like this which will remove all text from a period to the end of the string.
Find:
\..+$
Replace:
Nothing
You could change that to:
[.!?].+$
To accommodate more punctuation marks.
-Chris