Download a torrent client (like uTorrent), then you can download the episodes you want... delete after you finish :D
Here is a link to the Survivor AU:
Extra Torrent
or
The Pirate BayBUT, if you go to TPB, make sure you have ghostery/adblock/noscript.. it is loaded with ads and hidden scripts :p
and make sure you get season 3.. the first 2 seems to be terrible :p