is there some way to glue the sticker back on because the bottom right edge of the sticker wont stay on the R4 or can i buy the sticker somewhere
are you really bothered about the sticker!? you could remove it
or cut it carefully just above where its still stuck down with a sharp knife like a craft knife or something just don't press too hard so you don't cut into the R4!
don't think there's anywhere that would just sell the stickers you could always buy printable stickers and try make your own ... but maby you would be just better off peeling it off its a solid back and front so will not really matter .....
the other alternative is to find someone that got the original R4 first series that came with a white casing and a black casing and see if they are willing to sell their spare unused casing ...then all you need to do is swap the board out into the new casing and screw it back together again