I've not had a hysterectomy but I have had major abdominal surgery with a three year old and a toddler.
I'm afraid the only answer is childcare for four-eight weeks. You do need to look after yourself and make sure you can recover properly.
Who can you call on? Grandparents for a week at a time? Can your DH get some form of compassionate leave from work? My DH gets two weeks a time from his very large employer. Do you have siblings who aren't at work all the time?
What about friends? Can your friends arrange a rota? Half a day at a time? Either in your house or at theirs. A couple of years ago my friends banded together and covered three mornings and two afternoons a week for about six months. My DH worked from home and did the lunchtime cover between friends coming and going.
If you can afford it (or your parents can!) I would get a nanny for two-three months. If you can't afford full-time you might find you can get a part-time nanny, maybe bringing her own baby/child which reduces the hourly rate. You could then get friends to help out the rest of the time.
Good luck. Major surgery with small children is tricky. I've spent thousands on childcare for illness in the last three years. We have a leaking roof, buggered washing machine, inefficient tumble dryer, broken dishwasher, no holidays or at grandparent etc etc but the children have been well looked after!