You are asked to purchase some donuts at $1 each, a few bagels at $1.50 each, and several muffins at $2.50 each. Let d represent donuts, b represents bagels, and m represent muffins. Your boss then tells you that the number of orders have increased and that you need to purchase an extra three donuts and two more muffins. What is the expression that describes the cost of these items?