It takes 3 things to remove pet odor from furniture:
1) Nature's Miracle (get the gallon bottle sized....maybe pick up a few of them)
2) shopvac -> beg borrow or steal one, this is necessary for this to work - DO NOT use a regular vac
3) time...dont expect this to be fixed overnight.
Put the furniture somewhere that it will be left alone for a few days at a time and you have room to turn it over, etc. Soak, literally SOAK the affected areas with nature's miracle. saturate the cushions, seating area, etc and make sure that every square inch is wet (you might want to test a small area first to make sure it doesn't discolor the fabric, but since the couch is essentially ruined if you can't get rid of the smell, it doesn't really matter).
Let it sit at LEAST overnight, then shopvac the hell outta that thing. Make sure you dump out the cannister regulary otherwise the shopvac will start spitting smelly liquid out of the exhaust port. When you think you have it totally dry, vac it again.
Now, here's where time kicks in....DO IT AGAIN.....and again if necessary. Nature's miracle, and other enzyme based pet cleaners take time to work....you could wait a day or two before re=application, but I'd do at least 2 - 3 rounds before you take a break.