Welcome to the site;
This looks like it's been a ongoing problem for some time. There won't be any quick fix cover it up trick here. On the outside the perimeter drain isn't carring the water away, and the wall isn't waterproofed properly. Deverting the downspout away from the house and checking the grade of the land so no water is sitting against the house may help. On the inside, the drywall and insulation needs to be removed from the bottom of the wall to allow it to dry and inspect it for mold.