UV map it. If you used 3ds max look up some tutorials. If milkshape you are basically screwed. If that deep explorer paint thing program then look up some tuts.
Not really. I am not entirely sure how UV maps work but it is applied to the mesh and when that is changed the UV does not know what to do, so with an entirely new model it randomly places the textures. You could post a thread in the project recruitment area asking if someone could UV your model.