I strongly suggest you obfuscate this using a free obfuscator such as
Eazfuscator.NET to prevent people from using Reflector (which is free) (it can decompile any .NET application and display it in the language you wish) to get your source.
I'm a C# programmer too, and will gladly help you if you need help (but I can't help with .gba format, sorry)
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C# Programmer on the freaking loose.