Check in the classifieds, usually there are many postings related to what you want.

On the other hand if you want something more formal you will have to approach the "private transportation services" available in some of the shopping malls for further details.

By the way when I arrived I hired a driver from the "limousine" service from City Center and it was such an AMAZING service that from time to time and when needed we still call that person for help.

Regards!!