I just purchased the G-scale Christmas set "The Night Before Christmas" and would like to add a few additional cars to it.  As this is my first train ever I have a few questions.

1)Are there any additional Christmas cars available and where would I find them?

2)Will any car manufacturer work with the Bachmann I purchased?  If not which ones will?

3)Is the engine capable of pulling 2 or 3 additional cars?

Thanks
Chris