Replacing the mirror

So guys i didnt know where to put it so i am putting it here.
I am a beginner in blender and i was modeling a character using a mirror.(half cube half mirror) And now i want to know how do i replace the mirror with real… eh… material? Thanx for any help. Sorry for my english…

You just have to apply the modifier then you apply the material to all the object.

press the apply-button in the mirror modifier

Guys thank you so much. It was so simple…