Ok, I figured it out! I hope you have access to your old laptop...(or another windows device w your steam account and the game downloaded probably works too)
From my windows laptop:
1) Steam app > Library > Our Life: Beginning and Always > Manage (gear button on the right side of the screen) > Manage > Browse Local Files > Game (folder) > You'll see dlc_step_1/2/3.rpa.
2) Copy these three rpa files and put them into google drive.
From my macbook:
3) Download these three rpa files into macbook
4) Finders > Left click OurLife.app > Show Package Contents > Contents > Resource > autorun > game
5) Copy downloaded dlc rpa files into the game folder
6) Close and open Our Life game. Check the DLC menu on the main menu and everything should be installed.
Hope this helps!