The version of IE10 that you install depends on the Win 7 version you are running. I assume you have the 64 bit version installed.
You need to download and install the IE10 version for Win 64 bit.
Once the installation is complete you will notice that both 32 bit and 64 bit versions have been installed in the appropriate Program folders.
The 32 bit version runs by default and even if you run the 64 bit one it will still be 32 bit. The reason is that if you want to run the 64 bit then you need to enable it: How to Enable 32-bit or 64-bit Internet Explorer 10 (IE10) in Windows 7
I should add that for most users the 64 bit is not useful because of compatability and add on issues.
I hope this helps.