I have 7 years experience in JAVA, J2EE, API and ready to work on your project. I did similar project which will just updates a website the conversion value from the following site : Bitrex, Btce, Bter, Cryptsy, Mintpal, Poloniex, Vircurex. For every site I used their REST API to get the market value. But in your case we need more than this user details which we need to call the API with username and password of that site. Since getting pair value doesn't require any authentication for the APIs.