Well technically you were not bumped (oversale), your flight was cancelled and AR appear to be attempting to reroute you to your destination.
In Europe the cancellation would be subject to Regulation 261 but if it was outside of their control (for example weather) no compensation would be payable. They do have an obligation to reroute or refund.
In the US I don't believe airlines have any other obligation than to reroute or refund.
I tried to find AR's conditions of carriage but could not. They should have one somewhere and it should detail their responsibilities. But I doubt they would offer anything other than reroute/refund.
Good luck