L.N.
hi and congrats
i am a mom of twins. they're 4 years old. i guess my best advice is wait a little, i'd say until december then go offer your employer to telecommute and maybe even get a paycut while you do this from home. don't give an end date to telecommuting. wait and see what he/she says. if he/she starts dwelling on the idea, remind him/her that he won't have to pay for office space, computer/internet, telephone etc.you also benefit...stay home with kids, and save on gas and nerves :)
i have worked from home since 2003 but the type of job i do allows me to work full-time from home (no supervision), so you need to know whether you could do your job at home.
i'd say if you're allowed this, then do it until twins are 18 months then choose a place for them.
as for nanny thing, i can't offer any advice. i stayed home with girls (still do) and just rearranged my work hours (during naptime, quiet time), and then after DH came home he'd needed to take over for the rest of the night (after turning 1), which gave me from 8 pm to 1-2 am. that way i could put in all the hours needed. also, if i stayed behind with work, i made up during weekends.
good luck