What is needed is a “brute force” probe, that is basically an armor plated ball with an engine out the back. And not just any engine, but an advanced ion drive.
http://en.wikipedia.org/wiki/Ion_drive
It would be the first probe designed entirely for the exploration of deep space. Once outside the solar system, the armor plates would open, so the equipment inside would not have been degraded by radiation and particles within the solar system.
My theory is that, at the rate we develop technology, anything we throw at deep space is just going to get overtaken by something faster that we invent in the future, before it ever gets anywhere interesting. Which is why the premise of Star Trek: TMP, with Voyager returning to Earth was so silly. When the Enterprise went on her maiden voyage, she would have passed by wherever Voyager was puttering along at in a few minutes’ time.