Birth control as an emergency contraception?

Aria • I like strawberries.
I've been off birth control for about a week and a half and I was going to start back taking them tomorrow, but I had unprotected sex today. I know you can use birth control as an emergency contraceptive, but it doesn't have any specifics on Microgestin. Does any one know how many I should take now and then how many twelve hours later? I don't have money for plan b so please don't tell me "just buy plan b" or ask "then why were you having sex then".