You should apply to an insurance agent or company (lik Zion, Klala, etc. - see the Yellow Pages). There is a "manager insurance" (bituach menahalim) for employees which covers, among others, a sort of pension plan. I'm not sure how it works for freelancers, it's probably much more expensive, yet it exists.
Good luck,
Yael
PS - since you're a translator - would you please contact me by e-mail? My address: [email protected]