Just to let you know, the stream is coming in perfect for me, so we know that the stream is being broadcast fine out to the world.
From there it comes down to mostly your PC and how it's setup and/or your provider and what kind of speed you have.
going to speedtest.net and checking your speed is a good start
clearning your browser cache, making sure your graphic drivers are up to date, making sure your flash is up to date, maybe trying a different browser, are all things to try as somewhere to start.
When it comes to updating graphic drivers, I also say NEVER to update your drivers from the Windows UPdate. I have had too many pc's crash when they use those. A couple of different programs that will show you exactly what graphic card you have