Easily add the correct structured data using JSON-LD Google Merchant, this includes the missing microdata for condition.

header.php

<?php
// Locate the file header.php in your theme
// Before editing header.php, always make a backup so that you can roll back if something goes wrong.
// At the bottom of the header, simple add the code below
// Verify that you have done it correctly by checking the page with Google’s Structured Data Testing Tool
// https://search.google.com/structured-data/testing-tool
if (isset($product)){
  $meta = get_post_meta(get_the_ID());
  $_product = new WC_Product(get_the_ID());
  if ($_product->regular_price!=NULL){
	  $price = $_product->regular_price;
  }elseif ($_product->price!=NULL){
	$price = $_product->price;
  }
  if ( ($_product->price > $_product->sale_price) && ($_product->sale_price!=NULL) ){
	$price = $_product->sale_price;
  }
  ?>
  <script type="application/ld+json">
  {
    "@context": "http://schema.org/",
    "@type": "Product",
	  "name": "<?php echo get_the_title(get_the_ID()); ?>",
	  "url": "<?php echo get_permalink( get_the_ID() ); ?>",
	  "description": "<?php echo $_product->get_description(); ?>",
	  "image": "<?php echo $_product->get_image_id(); ?>",  
	  "aggregateRating": "",  
	  "brand": "",  
	  "review": "",  
	  "sku": "<?php echo $_product->get_sku(); ?>",
	  "offers": {
	  "@type": "Offer",
	  	"priceCurrency": "<?php echo get_woocommerce_currency(); ?>",
	  	"price": "<?php echo $price; ?>",
	  	"itemCondition" : "http://schema.org/NewCondition",
	  	"availability" : "http://schema.org/<?php echo $meta['_stock_status'][0] ? 'InStock' : 'OutOfStock'; ?>"
    	}
  }
  </script>
<?php } ?>

Added url and description.
image, aggregateRating, brand, review, and "sku"

Some are not populated because it will depend on wordpress / woocommerce setup.