Adding a shower to this bathtub
I have to comment that that tub structure is not really designed for a shower. You would have to install a shower curtain that draped into the tub on at least three sides to prevent water accumulation along the walls beyond the lip of the tub. 

As a suggestion you could look into a shower kit designed to convert an old style free standing tub into a shower but personally I think it would really uglify your bath area.