Sorry to hear of your predicament. It must be such a stressful time for you. I can't offer much advice on raising a child with Down's, I just thought I would tell you my friends story.
Are you 100% sure your baby has downs? I ask this as my friend was told her child had 1:157 chance of having down's so she went to genetic counselling, had amnio done and lots of other tests and everything came out clear and she had a healthy baby boy. She then got preg again and this time they said she had 1:82 chance. Again she had all the tests and couselling and she just gave birth to another perfect boy.
So before you make your decision, have the counselling and the amnio or CVS. Get as much info as you can and then see what may come of the situation.
Good luck with it all
Gold coast, DD 3.5years, DD 15mths #3 on the way