Do you have any other options in terms of schooling? That just sounds like a really bad school-kid mismatch. Montessori or other progress at your own pace type school, or a more developmental school? Homeschooling?
If none of those things are possible, here's what I would do, in no particular order....
1) I'd work on teaching her to read. Personally, I think six is a bit early to push reading, but I'd rather push reading than have a child have the self esteem issues of reading pushed in school and failing. I'd perhaps have some testing done to see if there are underlying learning disabilities. I'd order Cognitive Concepts Earobics and Sound Reading Solutions CD Roms to work on phonological processing. I'd get the I Am Sam books to work on decoding and fluency, and I'd pursue either ABeCeDarian or a Spalding based program (Spell to Write and Read, etc). Alternatively, Phonics Tutor or Funnix CD-ROMS for phonics instruction. And I would do lots and lots of reading aloud to her., for enjoyment. Once she has decoding under control and decent fluency, I'd work on comprehension (likely in a yr or two) with something like Lindamood Bell's Visualizing and Verbalizing or IdeaChain.
2) I'd work on cognitive skills via Audiblox and the Developing the Early Learner workbooks (Sonlight sells them).
3) I'd have her tested by a developmental optometrist and see if she needed vision therapy. I would get the Visual Perceptual Skill Building activities from Bright Minds to help strengthen visual processing even if vision therapy wasn't indicated. Might look into having hearing tested and getting a speech language and/ or OT eval.
4) I would do body work - look into cranial sacral therapy, chiropractic, sensory integration. I'd get Balametrics program and some Brain Gym books, do lots of outside play...bike riding, running, jumping on trampoline, skipping, playing with balls and bean bags, digging in sand, etc. I'd look into teaching her to knit and play the recorder, too (both work on crossing midline and build fine motor skills and concentration).
5) Math would be down there on my list in terms of priorities, but I'd try a couple things with her...maybe Kumon if she's more of a rote learner and you want a less intense supplement, or Right Start or Math U See math. Possibly Shiller if she's more multisensory, or Saxon even. Remember, you cannot rely on school to teach her things. You have to provide the foundation of her education. At this point for her, school will be nothing more than a demoralizing day care center. I hate to say that, but if she's at the bottom of the class and kindergarten is academic, that is really the reality. Esp if she doesn't qualify for special education.
6) Handwriting without Tears for handwriting.
I hope this helps. Good luck.
: for both of you!