How to make these shoes waterproof? or should I buy new ones?

There are several different brands of water "resistant" materials that you can apply to boots, However the products cannot make something "water proof". Add in the boot design failures and you get the same results wet feet. You want a "water proof" boot buy fishing waders, all boots will fail at a certain point what you need to do is read and compare the reviews of the different boots made out there and buy accordingly. The same with the coatings all work to a varying degree some better than others Buyer beware!