Leverage browser caching not working?

I’ve set up w3 total cache after looking through a couple of different how-to guides

including http://easysteps2buildwebsite.com/2013/01/w3-total-cache-plugin-settings-speed-up-website/ and http://onenaijablog.com/2013/04/how-to-speed-up-your-wordpress-blog-with-w3-total-cache-w3tc/

I’ve then followed this guide http://www.mvestormedia.com/leverage-browser-caching-w3-total-cache/

on leveraging browser caching – but when I run the google speed check my remaining high priority issue is to leverage browser caching. it’s still showing me a large list along with the message:

Suggestions for this page

The following cacheable resources have a short freshness lifetime. Specify an expiry of at least one week in the future for the following resources…

Please help :/

http://wordpress.org/extend/plugins/w3-total-cache/