How do you keep the ring volume UP and the bluetooth volume down?

I lower down the volume on my bluetooth headset while talking a call, it's too loud and I place the volume almost at the minimum. But then I found the iphone doesn't ring anymore (or barely rings) when someone calls me, just vibrates and I can not hear it anymore.

How do I set the volume for the rings on HIGH and the talking volume low independently? Is there an application that will enable that?

I only have ONE volume bar in the Sounds section, and will go down when I set my bluetooth device to low!!! I need one more, how do I set that up? Or, is there another option to keep these 2 volumes separated????

Edit: I have a 8GB iphone, 1.1.4, unlocked and with the installed working. I am not familiar with it since I just got it (my first Apple product), I am happy with it (I am coming from an N95 8GB with a 5MP camera) and I feel some feature really shorted, but overall I like it. I just have some issues I can (hopefully) fix, and I will live without my 5mp camera.