You will be able to transfer money from and Aussie bank account to your UK account, but I don't think you can pay UK companies direct.
I think it's a couple of dollars per transaction, depending on who you bank with.
Know nothing about Townsville, sorry; I live in Perth. When your visa is issued there is normally a time limit you have to cross the border by, but you can just take a holiday generally, if you aren't ready to move lock stock and barrel.
The visa costs can be looked up on the Australian immigration website its really helpful and explains so much, Townsville is a beautiful city and has I think the largest army base in Australia, my best friend is from Townsville and I have spent a fair amount of time there, the people generally are fantastic as are most Queenslanders, just be aware it is hot there all year round there is no getting away from it unless indoors in air conditioning and the humidity can be a killer hope this helps a little.
Transferring money would be better to do in larger lumps if possible then you can make use of the money exchange agents such as Ozforex, HiFX etc. I am affiliated with Ozforex - their minimum moving values are $2000 - you will get better rates than the banks. If you do want to use someone like Ozforex let me know as I can get you some free transactions if you go through my website.