Hi
If you play online / multiplayer mode, there is no need to move anything to your new computer. Just log in to SimCity and choose the server that you were previously playing. The regions should show up there.
Offline / single player games are stored on the local hard drive in your user documents folder; default location is C:\Users\<YourUserName>\Documents\SimCity\Games. Copy the contents of the folder from your old computer and move them to the same folder on your new computer. All your regions should be listed under the Single Player tab.
Happy Building!