If I may, what 64 bit driver? The last official driver for that card in either PCI or the PCI-E version was for XP from 2007,
FireMV
there never was a 64 bit driver for it from what I can find. Makes it that any 64 bit driver to me has been modified to add the necessary DevID for it to work. ATI/AMD also has separate drivers for their desktop and workstation cards, one reason none of the catalyst drivers will install on it.
In addition to not finding any 64 bit drivers for it, there are also no Windows 7 drivers for it as it is based on the desktop X600, a DirectX 9 based card that had support for dropped close to 2 years ago with the last driver for it (and any other DirectX 9 based card from the Radeon 9500 to the X1950 series) being a Vista driver,
ATI Catalyst
No idea if it will work or not, but you could using the above legacy driver with this INF (I added the DevId's from the last XP driver for that card to it),
View attachment CH_95951.zip
To add it either start the install as normal and after it has extracted itself and before the actual install begins, go to the extracted folder and locate the Drivers folder; will look similar to this,
C:\AMD\10-2_legacy_vista32-64_dd_ccc\Packages\Drivers\Display\W76A_INF
and replace the INF found there with the one above, then continue with the install.