Hello and welcome to Just Answer. How much did your dog eat and how much does your dog weigh?

It sounds like they ate it recently and if so it is good they are vomiting.

They will likely continue to vomit for a little while longer. As soon as they are done vomiting it is very likely that they will be very thirsty. The fructose is not toxic in its own right, but it can cause dehydration when that much is consumed.

Only allow then small amounts of water at a time. No more than 1/4 of a cup every 15-30 minutes.

Yes a walk would probably help. When their stomachs settle down you can offer them some burnt toast and if you have it some plain yogurt. The fructose may cause some bloating and intestinal upset.

The plain active culture yogurt will help with the normal gut flora that can be disrupted by the sugars. You can also offer them a half a teaspoon of Pepto bismol or Milk of Magnesia.

It is also possible that they got into something else in the trash, so if the vomiting does not stop, they seem very painful, stomach's bloat excessively, or if they vomit stuff that looks like coffee grounds or fresh blood, they should then be taken to the vet as soon as possible.

Please let me know if you have any other questions.

Burned toast can help absorb anything left in their stomachs, kind of like charcoal. I would hold off feeding too much else other than a bit of toast, or yogurt if you have any.