Angela sometimes a vertical incision is required when a baby had a certain abnormality because it makes it easier to get the baby out and will cause less damage to the baby than trying to manipulate it out of a biki cut incision. My sister worked in a fetal anomaly clinic for nearly three years, and believe me preterm is not the only reason to deliver a baby through a vertical incision. I'm sure the above poster has probably seen more than just her OB if her baby has an anomaly don't just assume that one person has told her this is the only way.
As to the OP, I would strongly advise getting an epidural instead of spinal so that you can be redosed during the surgery. A classical csection with a baby that has a birth defect will often take longer, sometimes 30 minutes longer. Also request to be completely sutured instead of stapled. This will give you a "better" looking scar and make you feel better put together. Have a firm pillow to hold against you to cough and get up to move once you get moving. It is going to hurt to bend and you will probably have a longer recovery time -- I personally would stay the full 96 hours your insurance will allow so you can have optimium pain management. Breastfeeding may be difficult (if you will be able to breastfeed), so if your baby can nurse, try the football hold or even the side lying position. Take pain meds on time, and don't be discouraged to take narcotics -- you will have so much going on with your baby that you will need to be pain free.
The biggest hurdle will be getting up and moving around the first few times and using the bathroom. Have adequate support and always call for the nurse when you do this. Even though it will hurt, moving around will be the best thing for you to do. Eat well and be sure to eat fiber and take a stool softner.
Some girls on the csection support thread may have some other advice for you. If you don't mind could you share with us what is wrong with your baby?