When were you thinking of hiring an attorney?
I suggest ... tomorrow.
This is too complicated for you to try to figure things out on your own.
NOTE: If you are low income go here: www.justice.gov/eoir/probono/states.htm or http://www.immigrationlawhelp.org/
PROFESSOR OF IMMIGRATION LAW for over 10 years -- This blog posting is offered for informational purposes only. It does not constitute an attorney-client relationship. Also, keep in mind that this is an INTERNET BLOG. You should not rely on anything you read here to make decisions which impact on your life. Meet with an attorney, via Skype, or in person, to obtain competent personal and professional guidance.
I would go anyway to show good faith although they will not adjudicate the case. They may reschedule the case or hold in abeyance awaiting the outcome of your conditional removal. If your marriage is no longer viable then you must get divorced and file for a waiver I-751. They may interview you and later if approved they will deny your N-400 since you applied based on marriage. Later after getting permanent GC and having been an LPR for 5 years you can reapply for the N-400. If the I-751 gets denied they may send your file to court called an NTA-Notice to Appear for deportation proceedings but you get a second bite at the apple to proof your I-751 waiver case called de novo (anew). But in order to proof a waiver I-751 you need to have a final divorce decree in hand and also proof your marriage was bona fide from the outset of legitimate and done for the right reasons not to obtain an immigration benefit. Good luck.
This is a very complicated situation, and I agree with my colleague that the sooner you hire and attorney, the better. I would not miss the interview, but I would want you to go with representation so your case is explained in the clearest way possible. It is extremely likely that the interview won't proceed as planned, but it will look better for you if you don't just skip out of the interview.
This general advice does not create an attorney-client relationship.
First step is to retain an Attorney to help you through this complicated process do not do this on your own.
Morales Law Firm P.A. 2100 Coral Way Ste 703 Miami, FL 33145 (305) 851-7856 This response is not offered as legal advice, but is only a general informational response for public interest. No one reading this is authorized to claim that an attorney client relationship exists with this writer or the writer's law firm.