So sorry that you had that "bad first agency experience", Navy RN.
To prevent wasting your time in the future, just call the different agencies listed in the yellow pages and ask them if they have anything for L&D nurses and if they expect all nurses, regardless of specialty, to take a general med/surg exam before hire, or do they have an exam for specialty nurses since that is the only place you desire to continue working. Also, many hospitals have perdiem pools that pay well. Have you checked into those? Since you are prior military, have you considered working as a Civilian nurse in a military hospital or clinic? I use to work as a Civilian nurse in military hospitals for so long that it was often tough on me going back to work for civilian hospitals. There is often a 180 degree difference between the two. It does take some getting use to. Also, some agencies contract nurses to work in military hospitals since this is a "comfort zone" that you know about already. Just tossing some suggestions your way. Best of everything to you in whatever you decide.
BTW, my middle daughter is prior Navy, and is now working as a civilian LPN at a Texas hospital. She said the differences between working civilian and military are soooo different, but interesting. She is working Newborn Nursery, but will be cross-trained to Postpartum, Mother/Baby, Ante-partum, and eventually L&D.