What do you mean with video grabber? And how do you plan the with the 3 cameras - only sequential images of individual cameras, or in parallel? Many simple frame grabber for monitoring functions can not really capture multiple streams in parallel, multiplexed to reduce the resolution, etc. How it looks at this card and if the multi-channel of Resolume can be addressed - noah planning. Now the downside risk at 18 ¬ is synonymous not very high. And yes they can sell it again if need be synonymous. If you want to edit multiple streams in parallel, it is possibly necessary to install several synonymous frame grabber that support a multiple operating on Windows.
I would anmailen Resolume the people themselves time and ask for appropriate hardware. The question of Win7 Drivers for the card would provide possibly synonymous, sooner or later.