Try Luzcar.
http://www.luzcar.com
They can provide you with a vehicle on arrival at Faro Airport.
I have used them for years.
Although their prices may appear slightly higher than others, the prices are inclusive apart from extra personal coverage. This also includes 2nd Driver and ability to take the car to Spain at no extra cost.
AutoJardim are also reputable.
http://www.auto-jardim.com/
