1) For adding it to Open Graph, you'd need to either a) create an Open Graph Plugin for JFBConnect or b) setup a 'manually' triggered action, like a button, that the user can click to post the action to their Timeline. Something like a button that says "I just voted". The plugin method would let you post it automatically when they submit their vote.
2) You can add the following Javascript to the page to create the Feed popup, like your image:
jfbc.social.feedPost(title,caption,description,url,picture);
Most of those values are self-explanatory (hopefully), but when implmented, it would look like:
<script type="text/javascript">jfbc.social.feedPost('I just voted','I just voted for xyz','Long description for the page','http://yoursite.com/voting-page','http://yoursite.com/link-to-vote-image.jpg');</script>
That could be triggered automatically on page load (the vote confirmation page) or 'hooked' into the voting button. We may be able to help you with some of that, but you may need a developer to assist as well.
Hope that helps,
Alex