Bulk Add Featured Image

This is maybe a bit of a long shot, but hey it never hurts to ask.
So i am Using WordPress 3.5.2 and Woocommerce to create a store and i am using WP All Import to pull in an XML feed from a supplier. All is working well, except the supplier does not host images,they are provided to me in a zip file. So instead of going through each and every product and manually adding thousands of Featured images i would like to run some sort of a script to set them automatically.

But i need some Help … Basically each image has naming similarities in connection with some detail in the product.

For example a product Title is Wolbar Abra and it’s image is albra.jpg .. i know it’s possible to define a url and make up the image name from the title using php … but the bit that i don’t know anything about is the actual WordPress side ..

So could anybody help me create a script to run through all products by category and add image based on URL ?

Greatly appreciate any help