Upgrade/Install SSL Certificate For OSCOMMERCE PAYPAL MODULE

We are in urgent need of a freelancer to update our SSL certificate, which has expired. Our website is on an OSCOMMERCE platform and our checkout process is via Paypal Express and Paypal Web Payment Pro. I don't believe this is a complicated job, but I do not have the expertise to do this and I am looking for urgent help. Ideally, we can get this done right away and discuss by phone.