Website and Facebook App

I want to create a Website from the beginning (starting by buying a domain), where me or an inexperienced programmer can work on ourselves later. The Design is less important, if it is possible to change it in the future.
The website must be able to:
- post topics which are able to receive feedback by the users. (The feedbacks should be able to be "liked" or graded in some way).
- sign up people and store the information on a database.
- IMPORTANT!: be accessed by Facebook users through a Facebook App! Like this: Facebook users who access our App will automatically be signed up in our website and will be able to post feedbacks to our posts via Facebook.
( - add an e-shop in the FUTURE!)
Roughly this is it. Also, the website will be in portuguese and directed to Brazil.
Anyone interested, please bid!

Kind regards