Are you still seeing the firewall icon? Yes theirs a brick wall infront of the earth
Did you double check your Win firewall setup? Yes theirs two Gnutella in Win firewall advanced, both ticked.
Did you try enabling UPnP within your modem or port forwarding? Nope

AFAIK Optus don't shape bandwidth. Does your internet plan have a download limit (just wondering if you've gone over your limit & so had your speed reduced - it happens on some plans)? Not sure