According to the WIKI :
Windows 7 is available in six different editions, but only Home Premium, Professional, and Ultimate are widely available at retail. The other editions focus on other markets, such as the developing world or enterprise use. All editions support the 32-bit (IA-32) processor architecture and all editions except Starter support the 64-bit (x86-64) processor architecture (64-bit installation media is not included in Home Basic edition, but can be obtained from Microsoft).
So should be able to get it from MS support.