Create a calculated atribute (product with % discount) and edit layout

I already give a 10% discount according to a payment method (Boleto). Another payment option is to pay with installments, which is calculated at the check-out. Now I need to show to the customers that they have this benefit. My webstore requires few adjustments: 1) Change the product display at home, category and brand pages to show: Price, Especial Price and Price with "Boleto" discount. It needs to show the maximum number of installments according to a min value. Example: a) I have a product with price $200 that I sell with a special price for $100. If I consider the min installment $10, the customer can pay in 10X of $10 with credit card. Or $90 with Boleto. b) I have a product with price $40 that I sell with a special price for $30. If I consider the min installment $10, the customer can pay in 3X of $10 with credit card. Or $27 with Boleto. 2) Change the Product page to show the payment conditions similar to the example above. If you are interested, get in contact so I'll send you the actual store adress.