If you are qualified, go to the USCIS office and apply for an advance parole travel document.
(213) 394-4554 x0 Mr. Shusterman is a former INS Trial Attorney (1976-82) with over 35 years of immigration experience. His response to your question is general in nature, as not all the facts are known to him. You should retain an attorney experienced in immigration law to review all the facts in your case in order to receive advice specific to your case. Mr. Shusterman's statement above does not create an attorney/client relationship.
You need to speak with your attorney as quickly as possible. While you may be eligible to file for travel permission while your application is pending, you may create a problem which does not surrently exist, and which may prevent you from getting your residence.
I would strongly urge you NOT to do anything without speaking to your lawyer first!!!
This answer is of a general nature and should not be relied upon as final, nor is it intended as legal advice. A consultation with an experienced attorney is always the best way to go.