Do you measure all your food or do you just 'eyeball it'? Perhaps you could adjust your portion size up - gradually, and watch the scale to see if you're gaining (in which case, cut back!) If your goal is to get all the recommended daily allowances in 1000 calories, that may be unrealistic. Or, instead of increasing portion sizes (which means increasing calories), bring other foods into your diet that are rich in vitamins and minerals you need.
Even eating 2000 calories, it's not so easy to get all the RDA in foods. Varying your diet tends to average things out so that you get enough, though.