I think you can argue about 2008 expense as you changed plans. They should cover you according to the new plan.
You also can argue the out-of-network doctor with hospital if the doctor was "assigned" to you instead of you seeking him directly.
Don't be angry and upset. Not good for you and your baby. Just talk to them calmly; and keep talking to them until the problem solved. (You can call the doctor/hospital regarding your bill. Sometimes, they are more helpful.)
About pregnancy coverage, I do know insurance policies explicitly not covering it (to lower premium). So, I feel the company did not do anything illegal.