NGUI Texture front of Sprite

I am new to Game Development and using NGUI plugin free version. There are few sprite images in my game. I made them prefab and instantiated at runtime. then I created NGUI Texture and Made it background. When I play my game. sprite prefabs instantiate behind the NGUI Texture Background. I want to place them front of NGUI Texture.I also changed camera Setting, now mainCamera depth is -1, and NGUI Camera depth is 1. changed both of them. But, could n't find solution. I have tried in several ways.

Any suggestions will be highly appreciated. Thanks