All pregnant employees are entitled to maternity leave. Not sure how your new resident status will affect your state benefit - it might be the lower end if anything at all.
Alot of companies don't pay salary or top up benefit to women on mat leave and I've heard of some if they do at all, that will pay only once a certain amount of service has been reached e.g. a year or two.
I'm not sure what happens if you are in a probationary period though once you tell your employer and start your leave. Maybe some one else might have been in the position here before and can shed some light on the subject.
By law, you only have to give 4 weeks notice of leave and your date of return to work.You are entitled to return to your normal job, i.e. that you were in at time of going on leave. You cannot be dismissed or be made redundant as a result of or during mat leave.