Dear G.,
I worked in the school system for numerous years. My middle son was still struggling with reading in third grade. What worked best to help him was reading aloud but softly as he read a book to help his flow and decoding. Use books lower than her reading level at first so she enjoys it and gradually increase the difficulty. This will improve fluency. Also, make sure she does know all the phonic sounds to the letters and sound blends (gr, fr, fl, etc.) Hooked on phonics is a game that could help. However, my son was a site reader and really had trouble decoding even though he knew the sounds. My sister gave me site books instead of phonic books to work with him. Some of it can be maturity too. I don't know when her birthday is or how mature she is. The comprehension problem is what concerns me more and she may have a learning disability. When you read to her or when she reads with you, ask her questions about what you have read...who said...?, what did they ... do next?, why did they do it? etc. Do this with TV programs she watches too and see if she is following them..if she can follow them and the story plot and answer questions it is less likely there is a comprehension problem.
As far as retention, first it depends on when her birthday is and also how big a child she is and if it is maturity or a learning disability. I actually have 2 of my three children back a grade...but did it at K. I also had two 5th grades and that was late and more difficult for me even though I was tiny and had a Nov. birthday...I should have been held back earlier. Since she is only in 2nd grade and you will be moving, if she isn't really big for her age or has a birthday that makes her really older than the others, she probably would benefit the retention. Actually a lot of parents of sons hold them back a year for maturity today since K is more like 1st grade use to be. If you are concerned about the comprehension after reading with her and having her answer questions about what she has read, you may want to see if you can get her tested by RSP (the resourse specialist program) to rule out a learning disability. (This is what my sister does who gave me the site books).
Have a wonderful, meaningful Christmas! I hope that this helps you with the decision that you must make in a few months,
H.