There are a few good places in Longmont that I know of and would recommend.
For auto repair I would highly recommend D & D Auto Repair, they are on 3rd Ave in Longmont (highway 119). Be sure to talk to Rob or Rudy, they are both the owners and do the work themselves. There phone number is 303-776-5628
For upholstery I recommend S & S upholstery, they are also in Longmont, right on Main St and 8th Ave. The owner there is Rex, he does some nice custom work. There phone number is 303-772-1155.
Hope that helps!