Is there eaves or a verandah? You could hang bamboo blinds from Bunnings that will shade the front. They're about $20 a packet and work really well. We used them on the front of a rental. We got the full frontal sun too and they were fantastic. We also used them on our own house to shade three massive windows and they worked so well we only really used the aircon on 35+ degree days, and even then it was only late in the day. Other than your own fix, there isn't much you can do as far as the landlord goes.

I agree with Divvy on the tree. The council is probably your best shot. You could tell your landlord that you're getting it inspected for safety.