I'm not super good at technical stuff, but I believe if you have the codes you can input them in Origin...if need be, customer service can help.
If you don't have the codes, then it's a bit trickier, but you can get an external disc drive (pretty cheap) and download them to your computer, but you will have to look up the working codes online. I used this combination of methods years ago, and play sims 3 regularly with all EPS, though it doesn't show that some of them are registered on thesims3 website because I didn't have my own unique codes any longer.