Originally Posted by sdrawkcab25

Welcome to the forums... I'm not too familiar with your phone, but I'll try to help.

Your phone, in theory, should automatically connect to the 3G network when not in range of your wireless router.(or any their router you've set it up to use).
If you aren't able to get out to the Internet when not in range of your wifi router, you will want to make sure you have mobile data turned on (would be in phone settings somewhere). You should also notice a 3G icon in the notification area of your phone(around where the signal bars/clock are).