Do you have codes for the base game and your other expansion and if so, did you try redeeming that on Origin ?
If not, I would get in touch with a game advisor so your games can be transfered to Origin.
Game advisors can be found through live chat.
- https://help.ea.com/en/contact-us/
- SET YOUR LANGUAGE TO US at the bottom
- Click on Contact a game advisor
- Describe your issue with a few words
- Click on Find a Solution
- Select Product: ex: The Sims 3 or Origin
- Select Issue Type: ex: Billing/Purchasing or Account Management
- Select Platform: PC
- Click Find solution
- Scroll down and click I still need help
- Click Chat Now to chat with a Game Advisor
With Pics here: http://sims3.crinrict.com/en/2012/10/how-to-contact-ea.html