1) You cannot upgrade from 32-bit Windows to 64-bit. It has to be a complete re-install.
2) And the hardware has to support 64-bit. Let me go look and see if that lappy does... As far as I can see, the answer is a resounding Maybe. Hast thou thy manuals or CD?
I suspect that that more-than-five-year-old laptop may not have good enough hardware to run Win7 for you, anway.