High risk!!! Help

My husband and I are wanting to have another baby. I am high risk. We have a daughter who was only 4 weeks early (pre-eclamsia). She is 4 years old now. She didn't have any trouble. Then in July 2006 we found out we were going to have a baby. He was due is April, but I went into labor suddenly in December. He was 1 pound 4.8 ounces. He was only with us for 8 months. Those few months were the best and hardest months of our lives. We want to have another baby, but are scared that I won't be able to carry he/she full term. We know a baby won't replace our son, and we know no one or nothing will ever be able to replace him. He was the strongest baby I have ever known. We have been trying since November, and nothing. We are getting so frustrated. We want to have another baby so bad. We are going to the doctor yet again, to see what we can to to help us. We don't know what to except. I haven't had trouble having them in the past, I'm just hoping that with my C-Section the doctors didn't do anything to prevent me from having a baby. I heard this was possible, maybe they cut you in the wrong place? I don't know. We just want to have a baby. If there are am suggestions please let me know.