I would recommend a ZAGG screen for the front and back if using without a case.
I like the 'speck' covers, and they protect nicely and fit well - I don't use a screen cover if I'm using the speck as it keeps the screen away from the surface you're resting on (if face down) by virtue of the bezel it has.
Above all, I would hang on until June. The new one will be out then, and IP4 prices will drop a tad, or you could just go for a new one.
Take a look on mobilefun.co.uk They have a huge selection. Covers from the market rarely fit well.