Hi R.,
I'm a student teacher in a second grade classroom right now. Here are a couple of things...have your daughter spell words to you throughout the day, so in the car ask her how to spell words, while she's eating breakfast, etc. If you notice she does better spelling the words verbally, ask the teacher if this is a form of intervention she can use with her (use either the word intervention or modification...those are important for testing purposes). If she's not willing to do that, then you need to talk to someone in admin about your concerns.
Also, don't be scared to get your daughter tested. She may not qualify for special ed, but she may qualify for extra help from a resource teacher or from regular classroom modifications. A little secret I learned is that if a parent requests that their child be tested it is usually a faster process than if the teacher requests it. Put it in writing to her teacher (make sure you save a copy for yourself).
For reading, you can buy a transparency and cut it into like 2" X 8" strips. Then, in the middle of each strip, use a highlighter to draw a straightline across it. Then, have your daughter use this when she reads. She puts the highlighted line over the line she is reading.
Some kids just aren't great readers or spellers, but she sounds like there is more going on. Make sure all the books she is reading (not what you're reading to her, but what she reads on her own) are "Just Right" books meaning that she can read and understand pretty much everything she reads in them. Have her read a couple of sentences in the middle of the book and then tell you what she read about. If she can't tell you, she was focusing too much on how to read the words and the book isn't right for her. Also, if she struggles with 5 or more words during a short reading selection, the book is not right for her.
Good luck, it really sounds like you're doing everything right. If the things you've been doing really aren't working, I personally think it might be time to pursue some other intervention at school.