Windows XP upgrade???

I am running 2000 on my computer and wanted to upgrade to xp so my girlfriend went out and got the upgrade version of xp home edition for me. That was great untill after I opened the box and noticed that it was the upgrade for windows 98. I took it back to the store to exchange it (and pay the extra $100) and was told that since the seal on the box was broken they wouldnt take it. So instead of mailing it back to microsoft and waiting for the refund I was wonderring if there was a way that I can make the upgrade for 98 to xp work for 2000 via a download or ect?