have you tried this site yet? They have all kinds of anime and video game content for sims 3. Just be careful I recommend running a virus scan after you go to the sites linked for each item, the content has never let me down, but it has given me minor viruses on my browser. Though these can be fixed by running a virus scan and restarting your browser if you use chrome. Not all the links give viruses just some of them so be careful and make sure you run a virus scan after your done though none of these should do any permanent damage to your computer, if you come across anything let me know, I will tell you how to fix it if you end up getting a virus.
http://animefinds.blogspot.com/