nvidia AFAIK manufacture chipsets only.they allowed different assemblers who give us options with tweaked/performace etc etc.
the best card brand seems to be EVGA,which recently are available in India though costly.
XFX is another good brand and distributor is Rashi Peripherals(South)
.
there is a site for PC dealers.check there for more infos:
*www.channeltimes.com/
also,
*www.nvidia.co.in/page/channel_partners.html
contact nvidia(india too):
*www.nvidia.co.in/page/contact_information.html