You sound a bit panicked about the whole thing so some organisation would help. Draw up two lists of people you would trust to look after your DC, including familiar babysitters/childminders. One list should be for during the day, another for night-time.
It sounds like your lists will be very short to start with as (a) your DC is quite young and (b) she's not in any type of ongoing childcare. You need to remedy this now - find some babysitters and start leaving DC with them for short periods to start with getting longer over time. Some ideas for babysitters - teenage children of friends/neighbours, girls from the local nursery/nursing college, older couple friends (with older DC or no DC).
You're going to need to be much less precious about who looks after DC. You and DH are obviously the best people for the job - however, both of you will be busy! It's not going to be for long - second labours are generally much shorter and even if your labour becomes prolonged, DH can pop back from time to time to check on her.
If this doesn't appeal to you, then you're going to have to be tough with yourself. Your DH can drive you to hospital with DC in tow but then he'll have to leave you as hospitals aren't the best place for such young DC. I say this having taken our 4 year old to hospital when I was in labour with DC2 - she still remembers me being in pain and the shouting and swearing 
I given birth twice without DH now - it's not ideal BUT you do get more attention because you're alone - the delivery midwives were wonderful both times. With DC3, I had a student midwife who I'd met beforehand when she asked if I could be her case-study. DH is obviously sad he missed both births but he was there shortly after as soon as he'd sorted the childcare.
Sorry for the epic post but you sound so negative and panicked - just thought you should know that if the worst happens (i.e. DH has to look after DC) it doesn't mean you won't have a great birth experience.