I wasn't aware that a video card is needed to transfer video from a camcorder to a computer. All I use is a firewire connection from my camcorder to my computer and Windows Movie maker. No additional driver is needed.
If your device was designed to do what you want and includes drivers/software and it doesn't work, then you should consult the manufacturer/vendor for help with the problem. Nexxtech does have a website and I'm sure if drivers are required they will be posted on their website. If not then ask them to send you the drivers.
Or if you can explain what happens when you install the driver, perhaps we can offer some assistance with the problem. You said "I have hard time installing driver" but we don't know exactly what you mean. Does the driver not install or doesn't work after installing?