I had sex with a black male ONCE on April 7, 2010 and sex with a white male on April 23, 2010 and every day after that for about 2 weeks . I am 15 weeks pregnant. My last period was on April 22, 2010 to April 26, 2010. Which one is my baby's father?

The one whose sperm got there . It is still too close together to tell until the baby is born and a DNA test is done. So it is just a waiting game at this point and time

No way to tell for sure.
You will have to wait until the child is born to tell.

i had sex with a black male ONCE on april 7, 2010 and sex with a white male on april 23, 2010 and every day after that for about 2 weeks . i am 15 weeks pregnant. my last period was on april 22, 2010 to april 26, 2010. which one is my baby's father?

Have you had an early ultrasound at all? The 15 weeks is from your last period, and in most cases you won't actually be pregnant in that first week or so afterwards. If your period on April 22 was normal in every way, odds are it will be the white man's. If it wasn't normal, it could be the black man's, but you would be further along.

Of course you may be able to tell not long after the baby is born simply due to how strong genetic features may come into play.

As the others have said, only way to know for sure would be to have some testing done afterwards. You could get the results in about four to six weeks.