Clone stamp problems

Hi everyone,

I'm stuck. I have to make a banner, but the orignal photo is too narrow.
So we needed to cut him into 2 pieces. left where the forklift is on, right where the rack is. 
But now I need to fill up the space inbetween with floor. ( see attached photos)

Does anybody have a trick for this? Because if I use clone stamp it looks spotted..

I also tried to content aware scale. But now the floor is really stretched.



Thank you so much for any tips