If you only see only 32bit in windows, it means that the processor is working at 32 bit. If the processor is a 64bit capable processor, it will work at 32bit by default. You need to change the settings in bios to 64bit then only you will be able to use the 64bit ability of the processor. Please check with your motherboard manufacturer for he settinggs to change in bios to enable the 64bit feature.
Hope this is helpful to you.