Hi,
I am quite an expert in moving sites from one host to another. I frequently do this for my clients. As I understand, you need to move two sites: HTML pages, php, asp and the related Database (MS SQLSERVER) to a different host. the 100MB size is not an issue. The databases will have to be backed up and the re-published to the new server. once the pages have been transferred, any absolute URL's will have to be changed to relative ones. There may be some issues with the scripts, But I can handle and rectify all of them.
Looking forward to hearing from you,
H