video grabbing

[FLIES at myia.imbb.forth.gr]

This is a question for the computer buffs among the drosophilists.  We at the
IMBB want to hook an old (but perfectly working) Mac IIx to our video display
so that we can get microscope images stored directly in the computer for 
further processing.  Our local Apple dealer says that the cheapest video
grabbing card that he could find costs the equivalent of 4000 US$.  Obviously
for this price one can buy a new computer that can do this without further
add-ons (e.g. AV).  Does anyone of you have any experience with such a matter,
and if yes (and cheaper!), could we have some advice?
Thanks in advance,
Kitsos Louis