The ABA (American Bar Association) has a LAMP program - Legal Assistance for Military Personnel.
Law firms and solo practitioners who volunteer for LAMP will work on behalf of active duty mility for free or expenses only.
You need a volunteer atty in Maryland.
Ck out the ABA site:
http://www.abanet.org/legalservices/helpreservists/lamphrdirectory.html
(I forget the guy's name who is in charge of LAMP- Bruce something - check the web site and call him if there are no longer atty-valunteers in that area of Maryland.)
You need someone to go in and set aside the Judgment.
The Judge will probably do this with your explanation.
Base legal may also be able to help (you need a lawyer in Maryland).
Unfortunately, I have found base legal/JAG to be sincere, but completely ignorant of all state court processes.
Some local Bar Associations may also do free work for active military (it's rare, and usually it's just wills and powers of attorney, but it doesn't hurt to try).
Call the Bar Association in that county in Maryland.
Do find someone quickly and move into court pronto.
If you can't find someone, as an act of last desperation, file a Petition To Set Aside Judgment with notation 'active duty military - default Judgment'. You have to file it in Maryland (you can file by mail), but you'd have to go back for the hearing date. Even if the form isn't technically correct, it just has to get on that Judge's calendar for consideration.
Let us know what is happening.
Good luck.