That is the exact tank that I have as well! but no, I do not have a male and a female, I was sure to get two males due to the fact that if they did mate I would have no where to put the extra fish. but I gave the swordtails to my girlfriend who has a much bigger tank, and they seem very much happier. She is going to hold them for me until I can get a bigger tank.
And thanks for the advice with the light. I usually leave it off all day because it is pretty dark in my room where the tank is and I turn it on in the evening so I can watch them. they are always asleep when I turn it back on so I know they are sleeping. I was just wondering if there was any specific time the light shoud be on for them.