Since she understands concepts but doesn't have the facts memorized, I would just work with her on that for the next several weeks/months, however long it takes. You don't need a curriculum to do that. Print some drill sheets, she could make her own flash cards, play computer games like Timez Attack. Since you have MM, she has a links at the beginning of each chapter for free online math games. Take advantage of that. Once she has her facts down fairly well, MM recommends 80% to move on, then you could most likely put her into 4th grade math and she won't be any the wiser of your concerns.
Math Mammoth has worked well for us and I've stuck with it, so hopefully someone else with a vaster knowledge of whats out there can recommend something for you. But whatever you choose stick to it!! Don't keep changing just because she doesn't like math. She may never enjoy it. ;)