I don't know the answer to that yet, but I have read that a copy of the 4.3 Toaster software can be purchased from NewTek on CD-ROM for a very affordable price. I have a Toaster 2000 card on the way (with 4.1 software, I believe), and I am going to try to get the 4.3 CD from NewTek when I can get the serial number off the Toaster.
Nice score on that second 2000, by the way.