brusca, welcome to the Seven Forums.
One thing to keep in mind is that that card hasn't seen a driver update since April 2002, Drivers for Discontinued ATI Rage
so I'm not surprised in the least that the XP 64 bit driver didn't work as there is no support for it in the driver. Also means there is not now and never will be a Windows 7 driver for that card.
All things considering you need a new card that does have Windows 7 support, either that or you continue using that old card with whatever driver Windows installs for it.