Solan to Hemkund Sahib

I am planning to travel to Hemkund Sahib from Solan from 27 Aug going to Manikaran and Paonta Sahib on the way. I would on the way back like to take the train from Dehra Dun to Amritsar. I am hoping someone can advise what car hire costs can I expect and where do I book a car from on the web. I am travelling alone.