To be fair, you shouldnt have paid for her ticket to her home country in April.Her employment contract clearly states that once a year is complete, she is entitled to a month off and a ticket home.
Regarding her being pregnant and married, until you see a marriage certificate, she is not married in the eyes of the law here so your best bet is to ask her to leave and send her back to her country. I wouldnt pay for her ticket, simply because you have already done that in April and I would actually remind her of that. If you want to give her a little something for teh baby its up to you but I wouldnt pay for another ticket for her. good luck x
Is your helper married? If not, and she is under your visa, I would send her home ASAP. But as her sponsor I think you are responsible for sending her home.