H.,
We had a heck of a time potty-training our son. Everyone kept telling us that when he was ready he would do it. We tried and tried for over a year to put him on the potty, encourage him, sticker charts, treats, etc, got VERY frustrated. Then, shortly after his 3rd birthday, he decided he was ready and was consistently going pee in the potty within about a week or so. He didn't decide he would poop until a couple months later, but again, as soon as he decided he was ready he just did it. As frustrating as it is, you have to wait for her to decide she's ready. My daughter is now 2 1/2 and we have been more relaxed with her about potty training. We started putting her on the potty at key times, like when she woke up in the morning, after nap, etc. We would read books with her or let her sit on her little potty and have a snack. She decided a couple weeks ago that she was ready and has been doing pretty well ever since. She still has some wet pull-ups throughout the day so I don't have her in undies, but she's doing well. As hard as it is, be patient. Keep offering and celebrate every little dribble or attempt. See if she responds to stickers or treats - I was so against that with my son, but it got him excited about the potty, so I ended up caving.
Another thought is, you said you work part-time. Does that mean your daughter is at a sitter part-time? If so, you could ask the sitter for help. I know people whose sitters have been in the business for so long that they have potty training down to a science, or at least are very helpful. Our sitter completely takes cues from the parents. She wouldn't let us stop giving her pull-ups until my son was very consistent, at least to protect during nap (she would put them over his undies), but she does support us by putting the kids on the potty to try, encouraging them, and giving treats.
Last thought. Be careful when your nephew starts wanting to pee standing up. Your daughter may want to try as well. That was an early hurdle for us because my daughter couldn't understand why she wasn't allowed to pee standing up since her big brother does. She would sometimes sit on the potty backwards just so she felt like she was being like her brother.
Hope this is helpful! Congrats and good luck with baby #2!