Your employers plan should cover you, I'd get on to both your HR departments and query this and complain if you have to, if a company wants you to move then they should cover you for all eventualities and shouldn't have a waiting period... although maybe you don't want to tell your employer that you're hoping to take mat leave so soon after arriving here! Definitely check the details as having a waiting period on a corporate policy sounds unusual and a waiting period before conception sounds unusual too. Usually the waiting period is as Gemma described, having said that, my experience is with international companies here.
It is standard for private policies that you take out to have a waiting period for maternity and some other conditions, otherwise everybody would only bother to get coverage when they knew they were pregnant and stop straight after they had the baby. The shortest waiting period I found was with DKV which is 8 months but it can be up to a year with other insurers. It does mean that you can start claiming after the 8 months is up - for example if you are already four months pregnant by the time the waiting period is up then you can't claim for your first four months of treatment but you can for the rest of your pregnancy and the hospital stay which is the expensive bit.
What Gemma said for the costs, about 1k a visit although it does vary depending on who you see, usually one visit per month and then one every two weeks as you head into the third trimester then the hospital bill depends on the hospital, type of delivery and any complications 100k is a good benchmark but of course it can be much less in some places and much more in others with complications.