Hacked! Help! I don't know what to do

I run the page cascadepolicy.org. When you Google my company’s name, Cascade Policy Institute, the “About” subpage link goes to a site for a Canadian Health Care site selling Cialis.

My WordPress AnitVirus widget says there is a virus suspect, and when I run the manual check, it shows lots of red boxes.

The “About” page on the actual website still appears to be fine. And I just updated all of the WordPress Widgets and the WordPress site.

Unfortunately, I don’t know what the hack looks like so I can remove it. I’m lost! Any help would be greatly appreciated!

Sarah