All the relevant info is in your database. You can probably connect to it, through a provider resource, phpMyAdmin and create a SQL dump, that will produce a single file with everything in there. You can use this as backup from which your database can be reconstructed at any time.
Data from databases is not simply readable or downloadable. The data is organized according to the type of database you have and the knowledge of that organization is required to properly access all data. That's what the forum code does.
That really depends on what mod you used to upload those files. Usually the files are uploaded to a folder named Uploaded or Upload and possibly to another folder inside this one, with the member's name. You need to FTP to your server or use a file browsing tool from your control panel, to determine where such files may be located.