Look into the writing revolution by Judith Hochman

http://www.thewritingrevolution.org/

I'm not quite sure something would exist for writing. I would try finding a tutor. Call ASDEC or Lab School. They may have some software recs as well.

I am looking for something similar to Aleks (http://www.aleks.com/), but for reading/writing. My child is in the 7th grade, and a very reluctant reader, who writes only short stories with simple sentences.

TIA