Well I have the expansion pack installed on my computer but I think i found where the information is stored. There are folders called UserData, UserData2, UserData3, UserData4, and UserData5. It looks like these refer to the different neighborhoods that are available in the Livin' Large Expansion. There might only be a UserData folder for the regular version of the sims. I think those folders are your best chance of moving your saved neighboorhood. Also check to see if there is an export feature built into the game anywhere.