I recently upgraded to Windows XP 64-bit but my wireless network card does not work anymore. So I need a new card that is compatible with Windows XP 64-bit, does anyone have any suggestions?

What you probably need are drivers. Almost every piece of hardware on earth has five drivers: XP, XP 64-Bit, Vista, Vist 64-Bit, and Mac OS X. You need the right drivers for the right OS. Just go to the company site and see if they offer new drivers. A lot of companies cram the XP and XP 64-Bit drivers into just "XP" drivers, since they're so very similar.