Hi,

Unfortunately there is no way to disconnect the alarm on this car effectively, as the majority of the alarm is located in the ETACS module which controls numerous other devices (locks, clock, wipers, turn signals....about anything that requires timing).

There are two ways to turn off the alarm in the event of the fob being missing. The first you already tried, using the key to unlock the doors while the alarm is going off. That is the standard method for disarming, however will not work if the key switches are worn out, etc.
The second method is only endorsed as a last resort method if there is no fob and the key disarm is not working, as it can pop a fuse. To do the second method, disconnect the negative battery cable, insert the key into the ignition and turn it to ON. Reconnect the negative battery terminal. This should power the car up with the alarm disabled.

If this method does not work, unless you have an add-on aftermarket alarm there is a high probability that something in your wiring was damaged in the accident. Considering it is a minor wreck, that is not too likely though.