The reason why SQL Server is much better than Access is unlike Access where you have a physical file you upload and download with SQL Server you connect to the database server to manage your database.
To move data from an Access database to an SQL Server database you can use the upsize wizard in Access to do this, but it will only work with a local network SQL Server. In your case you will probably need to buy a commercial tool that can migrate your Access database from Access to the remote SQL Server database.
Moving your forum database from Access to SQL Server is not something to be taken lightly. You maybe lucky and it only takes 15 minutes, but in many cases even our own engineers that do this on almost a daily biases and know the Web Wiz Forums database schema inside out can take up to 8 hours to do and get it right.
For this reason many people who move their Web Wiz Forums installation from Access to SQL Server move their hosting to us and then let us upsize their Access database to SQL Server for them as part of our migration service.
You can find details of our various hosting services at the page below:-
http://www.webwiz.net/webhosting/