How do I move the guest comments to same AGB w/dif. hosting?

I'm new to this type of code, would appreciate assistance.

I am moving my hosting service, and my new hosting uses the same Advanced Guest Book as the old host. I was wondering if I just copied the file the comments are stored in to the new host, that should do the trick. However, PHP seems to spread things all over the place (to my very untrained eye), so I have no idea where to even begin. Or maybe the copy idea wouldn't work.?? And if not, what should I do (short of retyping them all in the new book... ouch!) Thanks in advance for any help!