Hi JohnsonOng,
Elance.com is one of the best places to find ebook writers. Just make sure you choose ones with knowledge of the subject matter you want the ebooks written about (this will make it faster), and choose and Elancer with good feedback.
I don't have any experience setting up a website selling eBooks myself, but I see there are a number of guides available on the internet.
I will do some research on which one is best and get back to you :)