Snapshot not working for one of my sites. What are my other options?

Hi.

I moved hosts recently and I've been migrating all of my sites over one by one.
Most have been a breeze using Snapshot Pro, but one site is giving me considerable amount of pain. When I tried to do a restore of an archive file from another site, I got a "fatal error" message saying allowed memory size was exhausted.

So how can I move this site fully over? I'm guessing it's too large? Can I do partial move, and then ftp the files another way or something? If so....what are the exact steps to ensure a complete migration?

Thanks