How long is your day light hours? Is your plant exposed to night lamp? What is the temperature and light hours be like in the next two months?
What is the sativa mix in your plant strain?
Certain type of Sativa will develop buds with 11 hours light. Any light leak will delay flower development. After initial flower, Asian Sativa can takes two more months to develop flower. However, most modern strains blend in Indica genes to fatten the buds and five shorter flowering time.
Once the light hours shorten, then the buds get bigger magically. If you are in Australia, then, you better find a way to move your plant indoor in October. Else, It will be long wait.
I also grow out door. And I grow organic. So, to make buds bigger, I use guano (K rich) type with 1/4 strength. I also use molasses (2 ml per liter) once a week. And I add yogurt 1 part to 5 part of water, also once a week.