This is not something you can risk with homeopathic/or natural remedies!
You must make sure you receive your antibiotics 4 hours before delivery (EVEN IF YOU HAVE A C SECTION) and don't let them tell you otherwise!
Take it easy, very easy, You dont want to increase the risk of premature labour, if your hind waters break, they could leave you for a week befor inducing you, please be aware you are at increased risk of infection.
I am also gbs+ I had one baby fine and one baby with a gbs infection, the first baby received antibiotics and the second didn't!
Dont let them do unneccessary internal examinations, this can also increase the risk of infection.
But the most important bit of advice is get your antibiotics!
Teatree oil is an antibacterial, its good for healing but dont rely on it to prevent a gbs infection.