Hi,
1. Verify with webhostforasp that you are hosted in ASP.NET 3.5 SP1. If not request them to move you to that environment.
2. Assuming you have your database connection string in a user.config file at the root of your installation then you don't have to worry about losing your conection string when you upload the new version. So check for the existence of a user.config file and then check that it has your db connection string. If not look for the user.config.sample file and copy it, rename it to user.config, copy your connection string from Web.config to user.config.
3. Backup your current Web.config file on your local machine just in case.
4. Download the lates release mojoportal-2-3-1-6-mssql-deploymentfiles.zip. Extract the file on your local machine.
5. Connect to your hosting using the free tool FileZilla (an ftp client). Your control panel should have the needed info to connect via ftp or ask your host for help or check their documentation.
6. One you are connected with filezilla, upload first the /Setup folder from the extracted files so it overwrites/merges with the existing folder of the same name. Then upload the /ClientScript folder, then the /Data folder, then the rest of the files.
7. Visit yoursiteroot/Setup/Default.aspx so it runs the upgrade scripts.
8. You may need to re-selct a skin in Site Settings.
Hope it helps,
Joe