Here is a list of some great Places to stay please check them out online: The Ville Resort Casino Ardo Hotel Seahaven Resort Anywhere on Palmer street is also decent and close to wedding bus pickup/drop locations and the Recovery day Venue.
Average temperature in Townsville in Early August is very pleasant sitting around 20 degrees. It can get cool at night and drop to around 15 degrees so we would recommend bringing some warmer clothes just incase and maybe a light jacket for the Wedding Night.