I had a residential carpet installer, friend of a friend do mine the first time. I removed all the seating, bolted down stuff and old carpet, then he sent me to a carpet warehouse to pick out the new carpet using his discount... and I helped him install it. Only took a couple of hours. The worst part was taking up all the staples and pieces of the carpet pad that was glued down. There was also a lot of cutting of the old carpet under walls and built in cabinets/closets as the carpet and pad is usually laid by the manufacturer before the walls are built and everything is installed.
About 5 years later I replaced the carpet again but did it myself... took the better part of a day but I wouldn't hesitate to do it again if needed.
Sorry I can't point you in a direction for a company to do it... try asking friends about carpet installers they may know, check with the guy/workers that you have used for carpet in your home, or try contacting one of the installers that Home Depot or Lowes uses.