Honestly, having full siblings is not that big of a deal. My birds started out that way. If I had been able to keep any of the chicks alive, I would have had several males and several pullets. As it wound up...that didn't happen.
If I were you, I would breed the two females to the male. Keep their eggs separated from each other. Once hatched, breed a male from one hen to the "aunt" if you will, or you can breed the male back to the mother and maintain two separate lines. After a few generations, if you notice hatchability or vigor going down, you can use a male from the other "line" to increase vigor and hatchability.
Also, if you're wanting good quality birds, I would definitely wait until you have more funds. This will allow you to do your homework, look at different lines (by going to shows) and choosing birds that you know. You'll be able to study the standards for each breed and know what to look for in breeder birds. Also, most breeders are showing or are setting up their breeding pens, meaning that selling hatching eggs is not their number one priority at the moment.