I've deleted Google Play Store. How can I reinstall it?
You cannot uninstall the PlayStore/GoogleMarket app without having your device rooted -- so as Shedo guessed, you probably just uninstalled the latest update. Which means, the original app included with your firmware takes over -- and probably is called "Market" (the original name of the Playstore, before some market specialists started toying with the name).

So look out for an icon with a green bag, labeled "Market", that's it. Go ahead and start it, browse a bit, leave it. The Play Store App should be forced back on your device automatically -- maybe not immediately, but it usually doesn't take long.