Unless you're growing the onions for seed next year, it's best to pull them now and replant new in Spring. You might be able to get some decent growth out of them next year before they send up a flower stalk and get woody inside but I'd eat them now.

For garlic, it depends if they grew enough to produce cloves or if you've only got single cloves (rounds) down there. If you dig carefully around the bulbs you should be able to see if there are multiples or a single now (since the wrappers should have disintegrated) and if there are multiples you'd be best digging and replanting to give sufficient space to each clove. If you've got rounds, you can leave them in and they should come up fine either later this year or in early Spring.