Changing the computer the ipad syncs too - from PC to Mac

First off, let me say, I am NOT computer savvy.
That being said; I have ipods, and an ipad. I have always sync'd them to my MacBook. My husband got our sons ipads for Christmas and when he set them up he used his Laptop (not a mac). Now that they've installed all these apps, and beat many levels on Angry Birds and such games, I realized that they are not synced to the same computer that has all the other itunes info and apps (from my ipad/pods)

Is there a way to get the games that they've installed onto my computer (I do believe that both my husbands laptop and mine are signed into the same itunes account) so that they don't lose all their levels and scores and info? I know I can always re-install things, but it will take HOURS and they'll loose all their info.

When I hook it up to my itunes nothing happens, when I click the apps tab and click on the sync apps icon a screen comes up that says "...all existing apps and their data will be replaced..."
I did close my eyes and press "ok" and it showed the ipad screens on the side and their games where not there. I didn't sync anything and ejected it and it's all still good, but wondering what's the EASIEST most FOOLPROOF way to do this??
THANKS!!!!!!!
Sara