Facebook and Twitter marketing

I have a latest technology software product for realtors in USA. Need a Facebook / Twitter expert who can read sell my product in social Media. The posting should never look like spam or too much sales oriented. Please list your past experience. Should have a good knowledge about USA Real estate. How much will cost for 3 weeks. I need your to work for 4 hours a day for 3 weeks. I need results. I will share my website in Private message after going through your bid. We need estimate of sales you can provide using this marketing. We dont want false promise. We may need to use milestone payments. Remember the fans / followers are not important for me . Sales is the key.