You're welcome, HeffeD, and welcome to Mobileread!
Sometimes, when you're having problems like this, you never really know if the error is in the filter or the rewrite rule or both. One trick that I use (and used for this one) is to set your rewrite rule to:
www.google.com
That way, you can concentrate on getting the filter correct. When you are actually capturing your links correctly, they all get rewritten to send you to Google. At that point, you can start working on the real rewrite rule. Of course, there still may be errors in the filter, but at least you know you're catching the links.