Ex parte motions are not motions that require a written response. They are one-sided motions asking the court to act without the other side's involvement and usually involve extraordinary circumstances.
I would suggest that you do appear at the court hearing and listen to what the judge says before you speak. It may be that the judge will argue your side better than you could do yourself.
If you don't have legal representation, now might be a good time to find an attorney. Hope this perspective helps!
Your situation "cries out" for counsel. If you do not have one, check your court's website for a "pro se" office. The pro se staff member cannot represent you, but they can at least explain what is going on.
By your description it is unclear what the attorney filed. Given the tight timing, strongly suggest you write a polite and simple letter to the court, cc the attorney, that explains (1) who you are, (2) the current situation (ie just learned of motion etc) and (3) that you are respectfully seeking an adjournment of the hearing to allow you an opportunity to either retain counsel and/or respond to the ex-parte pleading. File your letter with the court (and be sure send a copy to the attorney) by 4pm today. Also bring a copy to the Court in an envelope marked "Chambers." Ask that that the Chambers copy be delivered to the Judge today.
I strongly suggest that you appear in court for the hearing to make sure your response is noted and your side of the situation heard.
The best way to respond is to hire an attorney who will both prepare a written opposition AND appear at the ex parte hearing.
The information presented here is general in nature and is not intended, nor should be construed, as legal advice. This posting does not create any attorney-client relationship with the author (who is only admitted to practice law in the State of California). For specific advice about your particular situation, consult your own attorney.