2001 Passat Need Help

Hey I have a 2001 passat with a broken driver's side wiper arm, which I need to replace, but I can't get the broken piece off. How should I get this piece off, should I bring it to a dealer, use a blade, or just more brute force, but if I use too much force, then I could rip out the entire wiper assembly. http://s214.photobucket.com/albums/cc232/toastermcfunk/?action=view&current=100_4252.jpg