You can consult your eye doctor when you are having an eye exam. He will give you some suggestions on what kind of frames are suitable for your prescription. You can either get glasses at your doctor's or go to any cheap stores to find the glasses that fit you well.
I think small frame glasses are better for your high prescription. Since you have high prescription, the plastic frame rather than metal frame will be a good choice for you because the slot of the metal frame is narrow. What's more, plastic frames have different fashion styles which provide more choice for you.