Resources managment add memory usage

Hi! I bought Unity3D my version is v3.2. My project contains ~300mb of resources (2d Textures and sounds). While playing the usage of RAM reach to 800 and more. Please tell how to unload unused resources from RAM and why this setuation is happend? For load texture i use function Resources.Load.

Unused textures can be unloaded with the Resources.UnloadUnusedAssets function.