Customising the RSS feed widget?

I’m pulling a RSS feed from the blog into the sidebar of the main site.

The blog is a separate installation of WP in /blog.

Trying to figure out a way to display thumbnails from the blog posts in the RSS but I can’t find anything to help. Unfortunatly I’m not well versed in PHP and am not comfortable writing my own code.

If anyone could offer some advice I’d be very grateful.

The main site is here: http://www.purplecircle.co.uk – you can see the RSS feed at the top of the sidebar.

Thanks!