Congratulations on receiving the holiday 2GB bonus! Must feel pretty nice to have an extra 2GB of data to be able to use for your convenience!
The even better news is, your 2GB Data Bonus Add-on doesn't have an expiry date! The 2GB add-on will remain on your account until you have used up all of it.
The way your data gets used in a regular month will first be by using the standard amount of data that comes with your monthly plan. Once you have used up your data allowance for the month, then you still start going into using part of your 2GB Bonus.
The same applies for the 500 minutes to call international countries!
The add-on will rollover forever until you have used it all up!