#1 Car seat and base - you'll need it to leave the hospital. Since you are on bedrest and even though you have a scheduled c-section date, I'd get this one ASAP and have your husband figure out how to install it in the car very soon. Trust me, this will be the last thing you/he will want to deal with in the excitement of the baby. You can go to www.seatcheck.org to find a location where a fire/police house will look at it and make sure it is installed properly.
#2 Swing and/or bouncy chair - Some babies love them, some babies don't. I think I might have lost my mind without having this. The swinging/vibration mimics some of the sensations the baby felt while in the womb and can be a source of soothing.
#3 Stroller - it all depends on where you live and how active you'll be following the pregnancy. You definitely will want one, but you might not need it right away. If I was still living in my downtown condo, with my car parked in a garage 3/4ths of a mile away a stroller would be a must (likewise, if you live in the city and have to fight for street parking and sometime have to park far away and/or you walk to all social activities or outings, you'll want one asap).
#4 Breastfeeding or Formula feeding? Make sure that whichever method you choose, you have the appropriate supplies for it. If you choose to use bottles, have your husband sterilize and wash them ahead of time.
#5 Clothing - Get just the basics and, like bottles, wash them ahead of time in Dreft or a chemical/dye-free detergent. Unless you truly care about your child being fashion-forward, just get some onesies, some pajamas, bibs, and socks. Chances are you'll get a lot of clothes at your showers and, quite frankly, the newborn sizes and 0-3 are outgrown SO quickly that if you have a ton of clothes there may be some things your baby never wears or only wears once. I know, clothes are the fun part, but save that shopping spree for 3-6 or older!
#6 First-Aid/Bathing supplies - You'll want a thermometer (your doc will probably want you to take his/her temp regularly for the first few days), cotton balls, infant Tylenol, Mylicon, diaper rash cream, isopropyl alcohol (for cleaning the thermometer). For bathing, I like the J&J ready-to-use washcloths (yes, they're more expensive, but one less thing to deal with when you're sponge bathing in the first few weeks with the baby screaming because he/she is naked!), baby lotion or oil, hooded bath towels. Sure, there are other first aid items, but they can wait until you're on your feet.
A word of advice...First of all, I love Babies R Us. I love going there and looking at all the fun stuff they have to offer. However, I'd caution against sending your husband in there to meet with a salesperson to say "My wife is on bedrest, can I have some help with what I need to buy?" because they will tell you that you need to buy the whole store. If you've ever seen their baby registry checklist, there is a TON of stuff on there that is completely unnecessary! Give your husband (or your mother or your mother-in-law or sister) a shopping list.