Importing previous data to a 'sequal'

[deValdr]

Easy.

Marshal.dump($game_variables, file)

You can exchange $game_variables with the following:
$game_switches - switches
$game_party - party gold and stuff.
+ all other data of your choice.

Exchange "file" with location of the file.

"Save_File.rxdata" saves it directly into the game folder
"Data/Save_File.rxdata" saves it into the data folder.

EDIT:
If you want to save more than one variable into the file (both switches and variables for instance), you should make an array:
@file = [$game_variables, $game_switches]
Marshal.dump(@file, "Save_File.rxdata"]