Maybe someone else will correct me, but I think Gee Wee is the same as what some say in the US as gee whiz. It doesn't mean anything really, it's just a phrase to express surprise or excitement, like 'my gosh'
As for "going night star" I think you're thinking of " go inna it star". Star is way of calling someone and giving them respect, like a star as in super star, someone famous, respected and/or talented. Go inna it star, I believe is a bit like saying 'do it, star' - an encouragement.