SH
You can upgrade from win XP to win 8
Windows 8 Upgrade Path for Windows XP:
Now let's talk about Windows XP. Good news for XP users. Windows XP users will also be able to upgrade to Windows 8 but they'll only be able to keep their document files after upgrading to Windows 8 similar to Windows Vista without SP1 users.
Also you'll need to have SP3 installed in Windows XP to be able to upgrade to Windows 8.
From here http://www.askvg.com/windows-8-upgrade-paths-for-windows-xp-vista-and-7/
BUT you may not be able to keep your Your apps, settings etc.
We have no idea what hardware you have but the path should work.
Win 8 system requirements are here
http://windows.microsoft.com/en-us/windows-8/system-requirements