I also managed to break this cable in the same way you did. I went to the Junk yard and got another one, including a new hood latch for good measure. Well I installed the new one, it worked great...two times. Then it broke the exact same way. I used vice grips also but kept shredding the cable.
So I gave up and cut the cable behind the grill and fashioned a handle that attached to the cable. Now I just pop my hood by pulling on the cable that is hidden (pretty well) behind the hood.