I am separated from my wife and my wife will let mee see my child but only when she is there. I want to able to bring my daughter home for weekends or to have proper contact, without my wife being there. I haven't done anything wrong and I want to see my daughter. Please help

So the court order for child custody and visit, what does it order ? If you don't have a court order, have you already filed ? If not, you need to file in court for visits. Until you go to court and get a order, and you allowed the child to live with her, then she is in control right now.
So visit with her but keep a record of her refusal to allow you to take the child. You will use that against her in court when asking for extended visits, or even joint custody.