You should be able to get Martin Senour paint at most NAPA auto stores. Go to <!-- w --><a class="postlink" href="http://www.napaonline.com">www.napaonline.com</a><!-- w --> and punch in your ZIP Code, and give your closest store a call and see if they can mix paint. 

I Googled [b:2enz1g7v]Madison, Wisconsin NAPA[/b:2enz1g7v] and [b:2enz1g7v]Janesville, Wisconsin NAPA[/b:2enz1g7v] and got several locations with each one, so there definitely some in your general area.