First off, if the hearing was postponed, then I disagree with your attorney's approach, and if you didn't have an attorney and you succumed to a continuance, that was a mistake (got to learn from mistakes or you will repeat them).
The longer the order stays in place, the more reluctant the judge will be to set it aside.
Anyway, you need to assess the truth of your situation. Are you a danger to your kids? Do you have anger issues? Are you controlling, hostile, argumentative, etc? If you are, then you need to stop, because the judge will see right through that stuff, because he/she does this all day long 5 days per week, 48 weeks per year, and you can't fool him/her.
That said, protective orders are the devil to undo because the parent seeking the order need only allege that she's afraid of you, and if it seems genuine to the judge, then the order will stick and you will be stuck.
You need some witnesses from the community who have seen you with your kids on a regular basis and who will testify that they've never seen anything even remotely approaching abusive behavior.
You need some witnesses who will testify to your ex's drug use.
You need a psychologist or psychiatirst who will testify that you are not using, don't have an addictive or controlling personality, etc.
You need to move the court to order drug and psychological testing on your ex before the hearing, which means another ex parte hearing.
And, you need to get over the fact that your ex will lie about you in court. EVERYONE in the family courtroom lies -- that's part of the program (even the baliff and the clerk are lying half the time).
This is just business -- not personal. You have to take the high road. You don't drink, don't do drugs, you're not aggressive and you have a great relationship with your kids, and your ex is a low down dirty drug dealing ***** who is a danger to the kids.
That's your position, but you will need a lot of evidence to prove it up.
Can you get it all? Not unless you have unlimited financial assets. But, you get what you can and put on the best show at the hearing that you can. If you don't, then you will lose.
Get a lawyer.