Move Windows hosted website to new hosting account

We have a hosted system which was currently hosted elsewhere which we require to be moved onto our own shared hosting plan.

We will provide a link which will download a zip file containing:

The systems source code.
Any files the system has (webapp/files)
A copy of the database

We will also provide logins to a plesk control panel, FTP and database details.

alternatively we can upload all of the files to the new host ready along with the database.

The system will need to be proved to be working on the new system using a host file redirect (or a temporary domain name provided by us), prior to us moving the domain across or purchasing a new domain for it.