While not a header repair utility, I had good luck in the past getting some deleted pics off a flash card using DIgital Image Recovery which is no longer available as a stand alone product but if you have access to the original media the pics were on, give it a try as you can use the evaluation version of ZAR software BJ linked to in his post.
Reading your post it sounds like everything was on the hard-drive. If that's the case, try Stellar-Phoenix. Search ts for links to it. It isn't free but you can try it and it'll show you what it can recover. If it can recover the pics, then only you and your sister can decide if it's worth the cost for a full working version.