How do i go from windows xp SP1 home edition to SP2 if my comp. is in a network? Not comp. literate..?

My comp. is 1 of 6 and is the only one still using sp1. The network is a wirless set-up. When i go to Micrsoft updates and downloads, I am told that I cont download from there. Is there a place I can go to get SP2 downloaded and installed for free? Please help?