I heard that nintendo stopped making games for the regular game boy. Is this true? Is there an adapter or something like that I can by so i can play the gameboy advance games on my regular gamebuy. I

There will never be a way to play GBA games on a GB/GBP/GBC.

It's time to upgrade to a GBA.
The Flash Linker is the only way to backup GBA games right now, but there is also something called the GB Bridge which allows you to put GB/GBP/GBC games on the GBA Flash cart.