Try eating more in each meal...
Snack on mixed nuts through the day, 1500 calories should be pretty easy to reach. A good bread would add 100 calories a slice but not sure how many you would want to eat in a day.
You are probably going to need to eat about 3 meals and get 500 calories from each, or eat slightly less than 500 in the meals and snack on fruit, veg, and nuts to get the rest