You can republish your site this way:
1. Log into your Yola account.
2. Select the site you need to republish. In the Sitebuilder, click the Publish button. This will update your live site with all the recent changes made as well as update your Form widget with the new reCaptcha.
You will know if your Form widget has the new reCaptcha when you see a checkbox instead of a box where you type in text and/or numbers.
The checkbox is the first piece of a large system upgrade to fight spam until all the pieces are in place the spam will continue to come through.