Sorry... forgot to answer that part.
Two options:
(1) Log onto
www.vzw.com My Account and it should say it on the lower right.
(2) Dial #DATA(#3282) on your phone, and wait for the two text messages to come. The second one should show you your KB usage. As long as your less than 5000000 (<5GB) at the end of the month (I'd keep it under 4GB just because I'm paranoid), you should be good to go. If you've already gone over, I'd just try not to go over again and hope you can skate by. BTW... 5GB is a LOT of data