Im pretty sure that 64 bit processors can support drivers. What you are probably thinking of is an operating system like Windows 64 or w/e which only supports 64 bit applications (I actually dont know if they sell this still or if it was ever a product). But yea a 64 bit processor should be backwards compatible with 32 bit drivers.
In most cases you'll have no problem with drivers when installing 64 bit windows.
You may have to search for some drivers for peripherals, but this has never been a major problem for me.
64 bit support is much improved from even a year ago.