please help!

hi!
I work for ID arte studio, which is a costarrican company dedicated  to web design.
Our company is made up by two people, myself and Gabriel who is the designer... we are arround 22 - 23 year old... but although our age, we have lots of experience by ourselves in freelance in TV, advertasing, film making, design. 
my part in the buisness is the marketing and sales stuff. I 've been reaseching about web and social media marketing. specially about "facts" and "stats" that  I can showto my client in order to present why a website is such an important tool for a company. I found lots of facts and statistics about social media, but its been kind of imposible to find real statistics for websites.... like for example, "companies with a proper website have increassed their utilities in X% since their realese in the web". the point is, that in my case, when I have a reunion with a client who is kind of new to the web universe, he or she, get convinced of the importance of web and social media for their company, and so: pay for it. (what it really worth)...
i would like to ask you, if you now about articles, books  or studies about the use of websites for diferent areas (from an art  portfolio to a restaurant, hotel or a shop etc) and how they helped to improve their services. 
we wiil be very glad if you can help us with this.

thank you very much for your time!
 

-- 
Cris Robles
(506) 88 44 74 03
Producción Audiovisual, UCR
www.idartestudio.com