Oh, very familiar with these Google feeds. Problem is the description element contains so much HTML including hrefs that you really would have to parse the entire description and pull out the specific links you want to redirect to a new window. That's more than a simple xsl transformation, kind of beyond the scope of this forum, I'm sorry to say.
Basically, you would need to take the description element apart and reformat it. It is possible, but it would take some more work in xsl to accomplish, and I'm not really sure if it's worth the effort. Here's why - newsfeed providers are notoriously protective of their news, which I understand, so, what happens is these news sources change frequently, and what you do to accomodate one specific provider has to be redone when they change their source provided. That's why the specs are around to help give folks a standard to facilitate 'easy' sharing. But with RSSv2.0 came more and more specialization and inclusion of html in the news source, which IMHO makes things much more troublesome. However, the providers want more and more control over the presentation of their news, not just control over the news itself. I guess that's to be expected, but it makes it difficult to use for content on another site, which is the real reason for taking those measures. Most of the larger providers do let you use their content on your site, but they are enforcing presentation rules more and more and are stricter about attribution of the source. Of course, it's easier to consume the news from your browser or standalone news reader which means you are using it directly, and not for content inclusion on another site.
I know this doesn't help exactly, but if you want to go into more detail shoot me an email.
Cheers