You cannot do an upgrade from a 32-bit OS to 64-bit because it requires a clean install (formatting the hard drive). As a result from your upgrading, only a 32-bit version of Windows 8 was installed. What you can do is download an ISO image of Windows 8 from your 64-bit Windows 7 laptop by following this:
How to download or re-download the Windows 8 ISO from Microsoft
There is a semi-official way to download a Windows 8 ISO image from Microsoft. Note that you can only use this method if you are running a version of Windows that you can upgrade to Windows 8 (basically Windows XP SP3 to Windows Release Preview, but not Windows 8 final).
Visit this Microsoft Windows website:
http://windows.microsoft.com/en-US/windows-8/upgrade-product-key-only
Click on the 'Install Windows 8' button there to download a 5MB setup file to your PC. You can change the language by editing the country code in the url.
Run the Windows8-Setup program on your system afterwards. Note that it will trigger an UAC prompt. Enter your Windows 8 product key.
If you do not have your Windows 8 product key at hand either use a program like Nirsoft’s ProduKey (http://www.nirsoft.net/utils/product_cd_key_viewer.html) to display it on your Windows 8 installation, or use the generic key XKY4K-2NRWR-8F6P2-448RF-CRYQH instead.
Note that the generic key will only allow you to download and install, but it cannot be used to activate the operating system. You need your own product key for that.
The program verifies the product key on the fly, and you get to a page where you have the choice to install Windows 8 right away, or create a installation disc. Depending on your connection speed, the setup might take few minutes to hours to complete downloading required files.
Once the download is complete, the setup will check the download for errors. And then you will see Install now, Install by creating media, and Install later from your desktop.
Select Install by creating media option and then click Next button. You will see save ISO file option. Select ISO file and then click Save button to start creating the ISO file. Once the ISO file is ready, you will see your product key again. Click Finish button.
You can use that downloaded ISO to create a new Windows 8 installation disc to upgrade an older version of Windows or do a clean installation instead:
http://www.ghacks.net/2012/10/27/windows-8-upgrade-clean-install-possible/