Would you get pregnant and do CVS testing if had 50% chance of ping on a life-threatening disorder?

I DESPERATELY want to have another child. My 5 year old already has this disease and I am depressed daily because I am afraid I will never have the chance to experience taking home a healthy baby or have grandkids. I cannot accept not having more children but we cannot afford PGD/IFV-- not covered by insurance. I also had an abortion when I was 17. I do not regret it but always think that there is a possibility that maybe that baby didn't have the disorder. I am thinking that I may be willing to do this once, but do not want to decrease my chances of successful IVF/PGD if we are ever able to do it. It breaks my heart every day when my daughter doesn't have a sibling to play with. Everyone says that only we can determine what to do, but we cannot. We are torn. I feel strongly one way at times and the other way too. This has been a decision going on for 3 1/2 years.