We arranged our own air several years ago. We contacted our hotel in advance and had them arrange for a private car for our transfer. The driver was not there when we arrived but a call to our hotel corrected that quickly. The advantage being that hotels typically will have someone who speaks English if there is a need. After asking several people at the airport, we found somone who spoke English and Chinese and initiated the call using my cell phone.
As a second choice, Google " airport transfer service Beijing" and you will see several private car companies offering the service. They most likely will also have someone who can respond to an eMail from you in English as they are in the business of dealing with foreigners.