I'd find a friend who has a faster broadband and download the installer there. Then copy to your USB stick and run from there on your machine.
But I've never seen a download time out. How big is the file (in MB), how far does it come (how many MB) in how many hours? What browser are you using? What is the exact error message?
I,m keen to try the Avast AV(free version at first) but my broadband is too slow (no dont laugh) to complete to download before it times out.
Is there any other place I can download from, other than clnet, that is less time restricted?