need a replacement driver for a brother A3 scanner

sounds like a simple task, download the latest driver from the brother website ? right ? unfortunately not that simple..so maybe somebody can help me?

problem is i have an A3 scanner (specifically: Brother MFC-6490CW) and I'm pretty positive the original disk is stolen as it contained a pretty good version of paperport , hence its gone!

i have since had to replace the PC that contained the original driver, and the present driver presents certain difficulties like correct print orientation and more importantly feeding documents into the scanner and scanning the wrong section as the scanner datum is the top left corner and scanning anything but A3 documents means you cant use the centered sheet feeder and you have to place everything on the glass one by one, plus as the downloaded driver is not appearing to work correctly i no longer have the opportunity to set the scanner to even scan A3 sized documents?

any body know if i have the wrong driver in the first instance? or has had a similar problem with this device ? or know if there is a better generic driver to do the job ?

Thanks