Hi there
I had 3 under 2 when my DTs were born (DD1 was 20 months at the time). I was very lucky - DD1 was in nursery (the daycare kind) 2.5 days a week and my mother came to stay for 2 nights a week initially, until I was able to drive (I had a CS), then for 1 night a week until the DTs were about 4 months old. So for the majority of the first 4 months I was very rarely on my own with all 3 at once. After that things got a little easier, although the first year is somewhat of a blur .
Do you have homestart in your area? If so, I would put your name down now for a volunteer - check with your HV. You wouldn't be able to leave the children alone with the volunteer and it would only be a few hours a week, but they would play with the older children whilst you got on with some washing or had a bath, or a quick nap. Also, if your older daughter isn't yet in a nursery, your HV might be able to get her into one sooner than you might have thought because of your circumstances.
Another route for part-time childcare is to contact your local colleges where they offer childcare courses. They often want homes for placements for their students. Again, this would only be for a few hours/a day a week and you couldn't leave them alone with the children, but they would be able to help you on outings to the park or the shops. Worth looking into this now, as they will probably be making lists of possible placements during this summer term.
So those are a couple of ideas for 'free' help...if you can afford to pay for some part-time help as well, the colleges might be a good place to start as well - some students might want some part-time experience after finishing their courses.
Hope this is of some help. Come over and join us on the regular thread as ooogs suggested - lots of mums with lots of children and lots of advice and support . It isn't always easy, but having twins is very special indeed.
And congratulations! .