the following is from the adobe documentation for sending the rating to the server:
index.html#anatomy
The Rating widget has a mechanism to send the user selected rating value to the server. You can choose the method to send data: GET or POST. The default method used to send the data is GET. If you want to send the data via POST you should add "postData" option in the widget constructor.
When sending via GET method you only have to provide the "saveUrl" option which takes the real URL for saving data. The widget constructor will look like:
<script type="text/javascript">
var rate = new Spry.Widget.Rating("spryrating1", {saveUrl:'SpryRating.php?id=spryrating5&val=@@rw_Rating@@'});
</script>
If you need to send the data via POST, you should add in the widget constructor the "postData" option- a string containing the url encode and the "saveUrl" - url for saving data. The "postData" string can contain the placeholder for the rated value, in this format @@ratingValue@@. It is always send in conjunction with saveUrl.
The widget constructor in this case:
<script type="text/javascript">
var rate = new Spry.Widget.Rating("spryrating1", {postData: 'id=spryrating2&val=@@ratingValue@@', saveUrl:'SpryRating.php});
</script>
use the postData method to convert the rating to a post, you probably need to add a hidden form element with same name, then you can add the binding in Universal Email to email the rating.
If you need further assisting implementing the postData, you should post in the Spry Forums, when you can post the rating, it should be simple to output into the email.