You have had good advice, rent a car, here are a few links to car rental places

http://www.nationalcar.co.uk/RatesAn...hire-Edinburgh

http://www.europcar.co.uk/car-hire-E...H_AIRPORT.html

http://www.avis.co.uk/default.aspx?c...d=t%2f0127584F

Let me know when you plan to visit Argyll, I will be more than happy to meet up with you and show you around

Chris