Seeking donor to give my little on a brother or sister

Hello- I am hoping to find a donor that can help my little family out. I am a unexpectedly single mother of a wonderful child. However, my clock is ticking and as I have devoted myself to my child, I have not attempted to start a new relationship. Even if I were to ‘fall’ for someone, it would not be healthy for all involved to jumpstart a family. So as I am running out of time- I am in my late 30’s, I am looking for a donor to fulfill my dreams of having a larger family and provide a sibling for my child. I am in NC and willing to travel- but not too far as my child is with me full time. Thank you.