Assuming you have 3 sow, you need:
1 farrowing
2 gestating
and around 2 fattening pen.
Proper size of pen
Farrowing: 1.6 x 2.1 meter, some say it should be 1.65 x 2.1 meter, or some use 5 feet by 7 feet.
gestating: .6-.7 x 2.1 meter
fattening pen: 3 x4 meter for 12 animals, in general you need 1 square meter per animal
i will send you a sample cost and return, just try to make some adjustment to it especially in the cost of feeds.