Solve the following math problem: Maddie wants to see how much her mom spends on coffee each week. She makes herself 2 cups of coffee per day. Each cup has 1.5 ounces of coffee beans. A bag of coffee costs $8 and contains 10.5 ounces of beans. She uses 1/2 a gallon of milk per week. A gallon of milk costs $4. She doesn't add any sugar to the coffee. How much does she spend on her coffee per week?