Without knowing the details of your ultrasound machine, I can't really give you much more advice on how to record video from it. I would try to find out if it has any sort of video output that can be connected to another monitor. S-Video is a popular output, I think. Search through the manual or talk to the person that sold the machine to you. Any signal that can be displayed on a monitor can be brought into a PC using a frame grabber. (I'm sure there is an exception to this rule, but they are very rare.)
Bruce
Bruce Ammons
Ammons Engineering