That is an insane story. I'm not sure what you can do about the mounts, but if Acura wants to play "hardball", you can too. As soon as you can, start the documentation process.

1. sales and transaction recipts from the Acura dealer
2. medical bills, if any, associated to the accident
3. police reports, if any, associated to the accident

You're not crazy, the motor mounts broke because the transmission locked up. With any Honda warranty, the parts and service is guaranteed for 1 year. If the transmission broke under 1 year, then it should be fixed again, no brainer. Since the transmission is bolted to the engine, the mounts broke under the heavy force ... once again a no brainer. Why Acura won't admit that, it's beyond me.

For $375, I think a lawyer would be more than interested hearing your case.