Sorry you're going through this! Are you in the US? One thing I would suggest is talking to a lawyer to see what the time frame is for having your expenses included in your claim against the driver. In Texas, you have 2 years to file a lawsuit, so even if you still hope to settle, you can file just to keep that option open. Most lawyers will give a free consultation, but if you retain them, they get a % of your award (I think it's 30% or maybe 1/3 if you settle, and more if you have to go to court). It was worth it to me just because I was stressed and hurting and just couldn't handle one more thing at the time.
Another consideration is that at least in Texas, the driver's auto insurance won't pay for any medical expenses until you settle, after which you can't make any additional claims. I was fortunate that my health insurance agreed to cover my expenses, although they filed for the right to recover their expenses from any settlement that I get. I've still had to cover the deductibles and co-payments, and I'm very grateful that I have a flexible spending account. Right now, I'm 2.5 years into treatment with 1 surgery and probably close to 2 years of PT for the various injuries (not just the shoulder). One more thing is to see if you have uninsured/underinsured motorist coverage on your car insurance policy if the driver's insurance doesn't cover your expenses.
As for the surgery, after my first accident I did therapy for my right shoulder (torn labrum, detached biceps tendon, AC joint damage) for about 6 months first, and the second time (left shoulder, torn labrum and AC joint damage) I waited about 18 months because I was dealing with concussion symptoms that were overwhelming. But when I looked at the bigger picture, I didn't want to have any regrets if I didn't do everything I could to recover as much as possible. I'm older than you - I was 48 for the first surgery and 54 the second time, and the prognosis is better for younger women. My right shoulder is close to 100% (it took about a year), and my left is probably about 80% after a little more than a year. One key is to find the best surgeon, and then just as important, the best physical therapist, and do what he/she says.
It seems that one option would be to wait at least until you're no longer nursing your baby. Do you have neighbors, church friends, or anyone who could help? I'd guess that someone at daycare could get him into the car for you. Maybe there's a young teen who could be a mother's helper and get him out of the car and help until your husband gets home??
Best of luck,