I believe your second price is just right based off the designs you posted. It's hard to tell which is better than the other. I noticed that for the most part you have one would-be style and at least one of the pages confused the heck out of me in terms of flow. However, if this is all your work then $1500 is good so long as you do not have to spend months on it.
Your potential client already took the ball and now she has you. At first it was a business person who needed to market herself and find a web presence. She was at your mercy. She hopefully saw your work and then asked for your services, or asked for your services, saw your work, and decided to continue. Whichever the case, she had to have seen your work and knows what you can do. She was pleased with what you could do and asked you for a price. You gave her one. Until that point you were the designer and she was the client. She may know what she wants and may be artistic enough to think of something that you can do, but she needs you. You should never enter into any agreement and decide to take less because you are desperate. It was at that point that you were on the verge of becoming her bitch. Then she knocked you down and you then became her bitch. Congrats on that one. No offense, but people like that jazz singer piss me off. She is making money doing her thing and then wants to talk you down. You need to send a friend to her for lessons and when she quotes a price have them take 40% off the top. If you think about it in those terms then she deserves to get a website that is 60% of what you can do. (i'd eliminate the unnecessary animation)
Do you get the drift?
So are you charging too much at $2500 for a woman who intends to use this site for both of her businesses to make money and market herself even more? No! Are you charging too little for a woman who intends to use the website as a marketing tool for web presence and to increase her cliental? YES! Should you take the job? YES, because you need the money and in the long run you can market yourself more if you had another client under your belt. But for future reference, if someone wants a site for fun then ok, lower that price. If someone is going to make money off of it, then look to see what they, how much you think they take in, and then charge the going rate or a competitive rate--enough to get you the job. If she has 10 students a week at $30 per student, 6 days a week she isn't doing bad. If she is teaching jazz singing and such I doubt she is cheep. I know my guitar teacher was expensive as all hell so it'd be a similar type of work I'd guess.
Don't take what I say as offensive. I think you cheated yourself, but I think she is to blame. I don't think you wanted to, but it's just as hard to pass up $1500 as it is to pass up $2500 so I do not blame you.