I lost my mother very suddenly and unexpectedly this past August. People just continuing to care is what has been the most help to me. The initial days you are overwhelmed with phone calls and visits and condolences. Then the funeral comes and goes and the rest of the world goes back to life as you know it and you don't. For me, this was when the real grieving began. This was when I needed people to be around, to check up on me, to be there.
I agree with what CAWriterMom said about specific things and not just saying "let me know if you need anything". Because right now, she probably won't have the energy to make that ask, or even know what she needs. The childcare suggestion is awesome. Preparing meals is a good idea, but be sure it is something they like (especially with little ones) and something they can freeze for later. We had so much food go to waste. Holding off and doing meals once she returns to work is an even better idea.
Practical stuff is great too, especially with little ones things like snacks, juice, milk, diapers, etc. are really important but probably really inconvenient right now for her to have to run out to get.
One of the nicest things my co-worker's did for me when I returned to work following my mom's death was to take me to lunch my first day back and just listen and let me cry. It was very overwhelming emotionally to go back to work, and having that escape was really nice.
Don't try to make it better, because you can't and she won't expect you too. I hate when people say things like "she is in a better place", "time heals all things", "she is still with you", etc. For me, I don't want people to make it ok that she is gone, because it's not ok. What I need is for people to let it be not ok, which isn't easy, but probably what she needs right now.