The lack of juvenile foliage (with many leaflets) and the weeping leaves suggest falciformis. With the limited information in the photo, I narrowed it to seven species on the assumption that there were 20 flowers per flower head, using the new free Wattle app. Information about how many glands there are on the leaves, how far from the leaf base, and whether the margin is indented at the gland, would help. Unfortunately, when I pressed the Best icon, the suggestion was Pod width. Diagnostics for Acacia rubida: http://worldwidewattle.com/imagegallery/image.php?p=0&l=r&id=23813&o=1 and for falciformis: http://worldwidewattle.com/imagegallery/image.php?p=0&l=f&id=23645&o=1
I am more inclined towards Acacia rubida for this one, flowering seems much too early for A. falciformis in the local area and the flowers seem too yellow. The flowers I'm used to seeing on local A. falciformis are more of a creamy yellow.