You can still buy the latest software directly from NewTek. I'm sure they sell to overseas customers.
EDIT:
This information is probably more helpful.
1. Call NewTek Customer Service at +1 210 370 8000 between 15:30 and 23:30 GMT.
2. Register your Video Toaster.
3. Order the following items:
ZVT/F4.3FloppyDisc Video Toaster/Flyer 4.3 Floppy Disc
ZVT/F4.3CD Video Toaster/Flyer 4.3 CD
The cost when I ordered was 50 USD plus shipping and handling charges. The kit includes software compatible with all Video Toasters.