Ok, MB, there's a lot of sense spoken above - if she does make an aggressive approach outside the work place, you both may need a court order.
As to you two, may I suggest letting grandparents/friends/godparent step in and take your child for a few days and get away to the country, a nice inn with good food etc.
You are on neutral ground, you can go for long walks etc, singly or together, relax a bit and talk this all through, what you feel, issues etc etc - have a look a smowball's thread as there is some related advice there too....from the talking, you can develop an "action plan", an awful term but you know what I mean, what both of you will undertake to stop this happening again......