Congrats. my EDD is also mid sept.
For the herbs and red date tea drink ingredients, you can visit Long wholesale at Rochor Centre, Bugis. Its 3rd floor on the rochor hawker. tell the person you are looking for confinement ingredients and they will give you a list of items you can buy.
i just bought yesterday.
For red dates tea, you have to buy red dates, black dates, dried longan, dang gui. that will be the basic.