Product and price options


I need some help with product options. For example I sell tiles. When customer is buying tiles - he has an option to choose:

  1. To buy product in square meters (m2);
  2. To buy product in pieces (pcs.).

    The thing is - i need to make 2 boxes where I can enter needed amount of product. And when I enter needed amount in m2, I need it to calculate the amount in pieces and show it in other box. Is it possible on Cs-Cart? Is there any modules? What is the solution?

    Second - Is it possible to set up a purchase price option for specific products?