How to send 12,000 emails a day..
You can send 500 emails per hour which is 12,000 emails a day(500 per hour x 24 hours in a day).
I am not sure if you are aware that you can use the SMTP setting hostgator gives you to send bulk mail.
Now I am not advocating spamming but maybe you have a large list you want to email outside your autoresponder.
Anyway, just sharing a useful tidbit that I use occasionally.