Are you using Windows? If so you'll probably be unable to do two-way communication using the computer's bluetooth. To do two-way, you would need to have the Bluetooth Mate Silvers at both ends. Ultimately, in software, what you're doing is exactly the same as having a serial cable (or usb-serial cable) connecting the computer and the Arduino... You will just have a wireless serial cable via the bluetooth connection. (So what I'm saying is, learn how to do serial communications back and forth)