You can change the default location that appears in your Open, Save and Save As dialog boxes.
Go to the File tab and click on Options.
Click Save in the left pane.
Click Browse next to the Default File Location box under Save Documents, and then navigate to the location you want to set as your default.
Click on your new default folder to select it, and then click OK.
You can change your default file type in which to save files here, as well.