Hi MRH - Welcome to w7forums
Every edition of Windows 7 comes in both 32-Bit or 64-Bit with the exception of Windows Starter which is only 32-Bit. You still have a choice of 32-Bit if that is your wish.
However most 32-Bit applications will work with the 64-Bit versions. The biggest concern with 64-Bit is finding drivers for your older hardware. If your hardware only has support for 32-Bit, you will find they no longer work with the 64-Bit Windows.
Go here and see what
Windows 7 Upgrade Advisor has to say. Download and install the application. After you run the utility, you can see what you may or may not have problems with.