Are there over-the-counter vitamins I can take for my menopause?

Yes. Black cohosh has been shown in some studies to show some benefit. There are also some yam products which have some studies supporting its use.
Yes. Black cohosh and soy are two of the most commonly used over the counter supplements. Other supplements like chasteberry, flaxseed, st. John's wort, and vitamin c may have some benefit but are not as widely used as black cohosh and soy.
Yes. The vitamins that are most helpful in menopause are vit d (2000 iu) & vit k (1-2 mg), which can prevent bone loss, one of the most serious problems in menopause. Vit e (400 iu) may reduce hot flashes- look for natural e with mixed tocopherols. Minerals like calcium, magnesium & strontium support bone health. Useful herbs include black cohosh, ashwagandha, purearia mirifica & rhaponic rhubarb.