CompuServe Messages

I own a DayStar Universal PowerCache 030 50MHz in my Mac IIsi, and I am having difficulty finding a 68882 math chip. I called the Chip Merchant, one of the largest chip dealers, and they did not have a 50MHz 68882! My questions are: 1) Where can I get such a chip? 2) Does it have to be a 50MHz chip? 3) Does DayStar sell them, and if so, how much? Thanks for your help. John Heck