You will have to reinstall all your favourite programs.

Boot from the Windows 8 64 bit DVD
Click Install Now
Accept License Agreement
When the option is displayed to select an installation type, click (Custom Advanced)

select the disk partition where you would like to install Windows 8 Click Next.

You will receive the following warning:

The partition you selected might contain files from a previous Windows Installation. If it does, these files and folders will be moved to a folder named Windows.old. You will be able to access the information in Windows.old, but you will be able to use your previous version of Windows.

(At all cost, do NOT click anything named Format or Delete or Partition. So even doing a custom install, your personal files are still preserved. Click OK

Setup will now start the installation. During the installation, your machine will be restarted several times.

When the installation is complete, you can complete the Out of Box experience such as selecting your laptop, create a username, password, your time zone. You can then proceed to download the latest updates for Windows and reinstall your applications and drivers.

You can then recover your personal files from the Windows.old folder and reinstall all your applications and drivers.

http://notebooks.com/2010/11/09/how-to-recover-documents-music-and-email-after-upgrading-with-the-windows-old-folder/

When performing the upgrade process the upgrade assistant determines your existing architecture, downloads the same architecture and installs.

To change from 32bit Windows to 64bit Windows a clean install will be performed (will have to reinstall applications etc…) and it will be necessary to purchase Windows 8 as a DVD.

Below is a web page that has additional information regarding Windows 8

Upgrade to Windows 8

You can go to a computer running a 64 bit version (Vista or Windows 7) and do the download there and create a bootable copy.

32 vs 64 bit

http://windows.microsoft.com/en-US/windows7/32-bit-and-64-bit-Windows-frequently-asked-questions

Windows 8 64 bit comes in handy when you need to address at least 4 GBs or more of RAM. Windows 8 32 bit can utilize up to 3.2 GBs of RAM. Because the memory address space is much larger for 64 bit Windows, that means, you need twice as much memory than 32 bit Windows to accomplish some of the same task, but you are able to do so much more, you can have more applications open, do things like run an Antivirus scan in the background without it affecting your system performance. Windows 8 64 bit is more secure too, malicious code cannot easily infiltrate it, drivers are more reliable since they must be signed before they can work with 64 bit Windows 8.

As for compatibility, you will need 64 bit device drivers for any hardware devices you might have. Also, there is no 16 bit subsystem in Windows 8 64 bit, which means, your applications must be 32 bit only, not 16 bit installer or uninstallers.

If you need to upgrade to the 64 bit version, you will need to do a custom over your 32 bit installed. You said you ordered the backup DVD with your order, so you will have the 64 bit disc.

You will have to do a clean installation, there is no in place upgrade path from Windows 7 32 Bit to 64 bit. Lauch the Windows Easy Transfer utility in Windows 7 and create a WET file (Windows Easy Transfer file), if you have an external hard disk, you can have it stored there so you can access it later when you do a clean install of Windows 8 64 bit disk.

http://www.notebooks.com/2009/10/07/using-windows-easy-transfer-in-windows-7/

Once you have done that, simply do a clean install of Windows 8 64 bit disk. In Windows 8 64 bit disk, launch Windows Easy Transfer, follow the on screen wizard, point to where you stored the the WET file (external hard disk), and it will restore your personal files and settings. Reinstall any necessary applications.