I think you should first play hand separated..
Then, when you are comfortable when playing one single hand alone, you speed it up more. e.g: instead of playing it at speed 10, try playing at 12 only with one hand. Never play with both hands until you are comfortable playing each single hand alone at a higher speed than normal.
Secondly, when you can play the first part of the piece with each single hand seperately and at a higher speed than normal, there is where you can play with both hands. If you play with both hands without first playing each hand individually, you may cause bad habits with your playing. (I know all of this cuz I read it on a book someone put here somewhere else)
Finally, I think you should need enough strenght in your finger to play this, also, play the left hand with the fingers paralel to the keys, not curved and extend the fingers how much you can. This will also expand the extension of your fingers.
I'm not a proper pianist to tell you this, but this is what I read from that book. So good luck!!practice also some exercises from clementi to gain strenght or try something else like czerny, etcetc