Big problem, and getting worse Dave.
You shouldn't worry too much about bringing them back on your person, as they only come out to feed at night. Your cleaning won't contribute much to solving the problem, other than if it makes your customer feel better to have you clean any dead ones out of the carpet.
During the day they hide out in bed frames,between mattresses and box springs, and around the piping/cording of the mattress. They also will crawl inside of electric sockets, crevices in nightstands, etc.
The exterminator rarely will get them all in his first visit.
If it were my place, I'd throw out the bed, the furniture, the carpet, all the clothing and other items in the room, and then I'd give serious consideration to donating the house to the fire department to burn down.
I put all of my clothes and luggage into plastic bags and douse them with pesticide after each time I have to stay in a motel.
These vampires have taken some people YEARS to get rid of.
It can be that bad.