Horse fitness plan (regimen)?

 
Horse fitness plan (regimen)?
OK, well Buttercup got hurt on Friday, October 15th (like 2 weeks ago) and has been on stall rest for over 2 weeks and still has 1-2 more weeks to go and then it will be at least 2 weeks before I can ride her. So all together its going to be at LEAST 5-6 weeks before she can be ridden. Shes really fit and muscular, ridden like 4-6 times a week for an hour and a half to two hours every time with jumping/flat work. I can already tell shes losing a LOT of muscle, and I worked SO hard to get her this fit and now shes going to lose it all :(.
So can you guys help me form a fitness regimen to get her back in shape for her when I can ride her again? For those who dont know her, She is a 6 y/o 15.2 hand palomino TBxQHxArab.
Thanks in advance!
(pics of her injury) - http://www.flickr.com/photos/53717496@N0