Dog emergency PLEASE HELP?

my dachshund is vomiting, collapsing and is having diarrhea i looked in my book and these are symptoms of heat stroke so i did what it said, "submerge dog under cool water" i did and he looks way better but his back hind legs are a little wobbly and he refuses to walk too much. I maged his back legs for a while and now he can make the effort to walk a little farther, what else should i do? Did i make a mistake? and please don't give me lip about this but our family is struggling with money and we cant afford a vet, HELP.