.net - Port Sqlite Application To A Server/client Application?

I have wrote an Application for a organisation and they had let the app run in their lan using Samba, it worked perfect. Now they want to work over the internet.The Problem is that I have written this app with Sqlite, that means its currently working so:They have a exe and the sqlite dll and the sqlite database on their samba server and they connected a network drive on their windows pc to run it. So that means every pc is writing over samba to the sqlite database.

I tried it over the internet, but like i thought sqlite is a local database and its very slow, even if the ping is under 50ms. I could create a tcp server, that handles all and writes all to the sqlite database, but I have already written around 20.000 code lines for the project, so that would be not the best option for the lazy me. I have used only one sqlite class in my client for querieng, so I thought that it could work without much work, if i would replace the sqlite database adapter with the mysql database adapter, since sqlite has nearly the same syntax then mysql.