Windows xp sp3 question please help?

when i go to the update site i find high priority updates and it says xp sp3 and its 60 some mbs is there some where i can download it so i can put it on a disc . because i have dial-up and a windows xp sp2 dics so if i ever reinstall i can install the xp sp2 disc then put in the sp3 dicsc to update it