you can look for cover cases made for your device here: http://www.sonymobile.com/global-en/products/accessories/
as for screen protectors. it would be not to use one, unless you are really clumsy with the phone, the thinner it is the better, so it wont affect the screen inputs, anyways since it work is to protect the screen you can change it when it gets scratches.
here's a tip from me: I use a microfibre pouch (usually the one that comes free when you buy sunglasses), its soft so it wont get scratched, and i place a microfibre cloth inside just for added protection againts bumps.
